diff --git a/Help/manual/cmake-instrumentation.7.rst b/Help/manual/cmake-instrumentation.7.rst
index fb6f244b67..09cb706c6a 100644
--- a/Help/manual/cmake-instrumentation.7.rst
+++ b/Help/manual/cmake-instrumentation.7.rst
@@ -456,9 +456,9 @@ Snippet files have a filename with the syntax
 
     The integer signal number that interrupted the command before it completed
     (for example ``2`` for ``SIGINT`` from Ctrl+C). Only included when ``role``
-    is ``cmakeBuild`` or ``cmakeInstall`` and the command was interrupted.
-    Consumers can use the presence of this field to distinguish an interrupted
-    command from one that ran to completion.
+    is ``cmakeBuild``, ``cmakeInstall``, or ``ctest`` and the command was
+    interrupted. Consumers can use the presence of this field to distinguish an
+    interrupted command from one that ran to completion.
 
     Only available as of data version ``1.2``.
 
diff --git a/Help/manual/instrumentation/snippet-v1-schema.json b/Help/manual/instrumentation/snippet-v1-schema.json
index 37731ff1a4..1b7e74049b 100644
--- a/Help/manual/instrumentation/snippet-v1-schema.json
+++ b/Help/manual/instrumentation/snippet-v1-schema.json
@@ -237,7 +237,7 @@
       },
       "interruptSignal": {
         "type": "integer",
-        "description": "The signal number that interrupted the command before it completed. Only included when role is cmakeBuild or cmakeInstall and the command was interrupted.",
+        "description": "The signal number that interrupted the command before it completed. Only included when role is cmakeBuild, cmakeInstall, or ctest and the command was interrupted.",
         "minimum": 1
       },
       "role": {
diff --git a/Help/release/dev/instrumentation-interrupt.rst b/Help/release/dev/instrumentation-interrupt.rst
index c930f2ced6..37681e723b 100644
--- a/Help/release/dev/instrumentation-interrupt.rst
+++ b/Help/release/dev/instrumentation-interrupt.rst
@@ -11,3 +11,8 @@ instrumentation-interrupt
 * Similarly, :manual:`cmake-instrumentation(7)` API now records an overall
   ``cmakeInstall`` snippet, marked with the same ``interruptSignal`` field,
   when a :option:`cmake --install` invocation is interrupted by the user.
+* Similarly, :manual:`cmake-instrumentation(7)` API now records an overall
+  ``ctest`` snippet, marked with the same ``interruptSignal`` field, when a
+  :manual:`ctest(1)` invocation is interrupted by the user.  On interrupt CTest
+  stops scheduling further tests and preserves its checkpoint file so that a
+  later :option:`ctest -F` can resume the interrupted test set.
diff --git a/Source/CTest/cmCTestMultiProcessHandler.cxx b/Source/CTest/cmCTestMultiProcessHandler.cxx
index 71a3ab4a4a..4954e0d55b 100644
--- a/Source/CTest/cmCTestMultiProcessHandler.cxx
+++ b/Source/CTest/cmCTestMultiProcessHandler.cxx
@@ -35,6 +35,7 @@
 #include "cmCTestBinPacker.h"
 #include "cmCTestRunTest.h"
 #include "cmCTestTestHandler.h"
+#include "cmInstrumentationInterrupt.h"
 #include "cmJSONState.h"
 #include "cmListFileCache.h"
 #include "cmRange.h"
@@ -246,13 +247,21 @@ void cmCTestMultiProcessHandler::RunTests()
   uv_run(this->Loop, UV_RUN_DEFAULT);
   this->FinalizeLoop();
 
-  if (!this->StopTimePassed && !this->CheckStopOnFailure()) {
+  // A user interrupt (e.g. Ctrl+C) deliberately stops scheduling with tests
+  // still pending, so skip the completion asserts in that case.  Canceled
+  // launches release their resources, so AllResourcesAvailable() still holds.
+  if (!this->StopTimePassed && !this->CheckStopOnFailure() &&
+      cmInstrumentationInterrupt::PendingInterruptSignal() == 0) {
     assert(this->Complete());
     assert(this->PendingTests.empty());
   }
   assert(this->AllResourcesAvailable());
 
-  this->MarkFinished();
+  // On interrupt, leave the checkpoint file intact so a later `ctest -F` can
+  // resume from where this run left off; MarkFinished() would delete it.
+  if (cmInstrumentationInterrupt::PendingInterruptSignal() == 0) {
+    this->MarkFinished();
+  }
   this->UpdateCostData();
 }
 
@@ -583,6 +592,17 @@ void cmCTestMultiProcessHandler::JobServerReceivedToken()
   assert(!this->JobServerQueuedTests.empty());
   int test = this->JobServerQueuedTests.front();
   this->JobServerQueuedTests.pop_front();
+  if (cmInstrumentationInterrupt::PendingInterruptSignal() != 0) {
+    // Interrupted (e.g. Ctrl+C): do not launch this queued test.  Its
+    // resources were locked when it was queued in StartNextTests, and this
+    // callback runs holding a job server token, so release both to keep the
+    // scheduler's bookkeeping balanced (see the AllResourcesAvailable() and
+    // token invariants checked after the loop).
+    this->DeallocateResources(test);
+    this->UnlockResources(test);
+    this->JobServerClient->ReleaseToken();
+    return;
+  }
   this->StartTestProcess(test);
 }
 
@@ -594,7 +614,11 @@ void cmCTestMultiProcessHandler::StartNextTests()
   this->StartNextTestsOnTimer_.stop();
 
   if (this->PendingTests.empty() || this->CheckStopTimePassed() ||
-      (this->CheckStopOnFailure() && !this->Failed->empty())) {
+      (this->CheckStopOnFailure() && !this->Failed->empty()) ||
+      cmInstrumentationInterrupt::PendingInterruptSignal() != 0) {
+    // A user interrupt (e.g. Ctrl+C) stops scheduling: launch no further
+    // tests. Tests already running receive the interrupt too and unwind on
+    // their own.
     return;
   }
 
@@ -650,6 +674,7 @@ void cmCTestMultiProcessHandler::StartNextTests()
   // Start tests in the preferred order, each subject to readiness checks.
   auto ti = this->OrderedTests.begin();
   while (numToStart > 0 && !this->SerialTestRunning &&
+         cmInstrumentationInterrupt::PendingInterruptSignal() == 0 &&
          ti != this->OrderedTests.end()) {
     // Increment the test iterator now because the current list
     // entry may be deleted below.
@@ -791,6 +816,7 @@ void cmCTestMultiProcessHandler::FinishTestProcess(
   }
   if (started) {
     if (!this->StopTimePassed &&
+        cmInstrumentationInterrupt::PendingInterruptSignal() == 0 &&
         cmCTestRunTest::StartAgain(std::move(runner), this->Completed)) {
       this->Completed--; // remove the completed test because run again
       return;
@@ -807,7 +833,12 @@ void cmCTestMultiProcessHandler::FinishTestProcess(
     t.second.Depends.erase(test);
   }
 
-  this->WriteCheckpoint(test);
+  // A test killed by the interrupt (e.g. Ctrl+C) never truly finished, so do
+  // not record it in the checkpoint; otherwise `ctest -F` would skip it when
+  // resuming this interrupted run.
+  if (cmInstrumentationInterrupt::PendingInterruptSignal() == 0) {
+    this->WriteCheckpoint(test);
+  }
   this->DeallocateResources(test);
   this->UnlockResources(test);
 
diff --git a/Source/cmCTest.cxx b/Source/cmCTest.cxx
index a0f24dbd93..758c61f7a1 100644
--- a/Source/cmCTest.cxx
+++ b/Source/cmCTest.cxx
@@ -52,6 +52,7 @@
 #include "cmGeneratedFileStream.h"
 #include "cmGlobalGenerator.h"
 #include "cmInstrumentation.h"
+#include "cmInstrumentationInterrupt.h"
 #include "cmInstrumentationQuery.h"
 #include "cmJSONState.h"
 #include "cmList.h"
@@ -2758,12 +2759,40 @@ int cmCTest::ExecuteTests(std::vector<std::string> const& args)
   };
   std::map<std::string, std::string> data;
   data["showOnly"] = this->GetShowOnly() ? "1" : "0";
-  int ret = instrumentation.InstrumentCommand(
-    "ctest", args,
-    [processHandler]() -> cmInstrumentation::CommandResult {
-      return { processHandler(), cm::nullopt, cm::nullopt };
-    },
-    data);
+  // Run the tests under an interrupt handler so that a user interrupt (e.g.
+  // Ctrl+C) still writes the overall `ctest` snippet before we exit.
+  cmInstrumentationInterrupt::InterruptOutcome testsOutcome =
+    cmInstrumentationInterrupt::HandleInterrupt(
+      instrumentation.HasQuery(),
+      [&instrumentation, &args, &processHandler, &data]() -> int {
+        return instrumentation.InstrumentCommand(
+          "ctest", args,
+          [&processHandler]() -> cmInstrumentation::CommandResult {
+            return { processHandler(), cm::nullopt, cm::nullopt };
+          },
+          data);
+      });
+  int ret = testsOutcome.ExitCode;
+  if (testsOutcome.Interrupted) {
+    // The tests were interrupted and the `ctest` snippet has been written.
+    // Skip the post-ctest indexing hook and make the exit status reflect the
+    // interrupt the same way it does without instrumentation, so enabling
+    // instrumentation does not change the exit code of an interrupted run.
+    // For a real signal, re-raise it on POSIX (the shell then reports
+    // 128+signo); on Windows our console handler suppressed the OS default, so
+    // report the status Windows itself uses for a Ctrl+C-terminated process.
+    // A test-injected interrupt has no real signal, so it instead returns a
+    // normal error status to keep the seam case deterministic.
+    if (testsOutcome.ShouldRaise) {
+      cmInstrumentationInterrupt::RaiseInterrupt(testsOutcome.Signal);
+#ifdef _WIN32
+      // STATUS_CONTROL_C_EXIT: the exit status Windows reports for a process
+      // terminated by Ctrl+C, which our console handler otherwise suppressed.
+      return static_cast<int>(0xC000013A);
+#endif
+    }
+    return cmCTest::TEST_ERRORS;
+  }
   instrumentation.CollectTimingData(cmInstrumentationQuery::Hook::PostCTest);
   if (ret == cmCTest::TEST_ERRORS) {
     cmCTestLog(this, ERROR_MESSAGE, "Errors while running CTest\n");
diff --git a/Source/cmInstrumentation.cxx b/Source/cmInstrumentation.cxx
index c50bb90f57..b0a2b6d37e 100644
--- a/Source/cmInstrumentation.cxx
+++ b/Source/cmInstrumentation.cxx
@@ -840,13 +840,13 @@ int cmInstrumentation::InstrumentCommand(
       }
       this->configureSnippetData.clear();
     }
-    // Write the cmakeBuild/cmakeInstall envelope atomically (temp file +
+    // Write the cmakeBuild/cmakeInstall/ctest envelope atomically (temp file +
     // rename).  This is the snippet flushed while unwinding from a user
     // interrupt, where a second Ctrl+C could otherwise truncate it mid-write;
     // the atomic write guarantees it is either absent or complete.  Per-step
     // snippets are never flushed under interrupt and are left non-atomic.
-    bool const atomicEnvelope =
-      command_type == "cmakeBuild" || command_type == "cmakeInstall";
+    bool const atomicEnvelope = command_type == "cmakeBuild" ||
+      command_type == "cmakeInstall" || command_type == "ctest";
     this->WriteInstrumentationJson(latestDataVersion, root, "data", file_name,
                                    atomicEnvelope ? Atomic::Yes : Atomic::No);
   }
diff --git a/Tests/RunCMake/Instrumentation/RunCMakeTest.cmake b/Tests/RunCMake/Instrumentation/RunCMakeTest.cmake
index 9a4cd0cc7b..b9a52e2fd2 100644
--- a/Tests/RunCMake/Instrumentation/RunCMakeTest.cmake
+++ b/Tests/RunCMake/Instrumentation/RunCMakeTest.cmake
@@ -16,6 +16,9 @@ function(instrument test)
     "INSTALL_SEAM"
     "INSTALL_INTERRUPT"
     "TEST"
+    "CTEST_SEAM"
+    "CTEST_INTERRUPT"
+    "CTEST_FAILOVER"
     "WORKFLOW"
     "COPY_QUERIES"
     "COPY_QUERIES_GENERATED"
@@ -135,6 +138,11 @@ function(instrument test)
       "-DINTERRUPT_BUILD_SRC=${RunCMake_SOURCE_DIR}/InterruptBuild.c"
       "-DINSTALL_INTERRUPT=ON")
   endif()
+  if (ARGS_CTEST_INTERRUPT OR ARGS_CTEST_FAILOVER)
+    list(APPEND ARGS_CONFIGURE_ARGS
+      "-DINTERRUPT_BUILD_SRC=${RunCMake_SOURCE_DIR}/InterruptBuild.c"
+      "-DCTEST_INTERRUPT=ON")
+  endif()
   set(RunCMake_TEST_SOURCE_DIR ${RunCMake_SOURCE_DIR}/project)
   if(NOT RunCMake_GENERATOR_IS_MULTI_CONFIG)
     set(maybe_CMAKE_BUILD_TYPE -DCMAKE_BUILD_TYPE=Debug)
@@ -313,6 +321,106 @@ function(instrument test)
   if (ARGS_TEST)
     run_cmake_command(${test}-test ${CMAKE_CTEST_COMMAND} . -C Debug)
   endif()
+  if (ARGS_CTEST_SEAM)
+    # Drive the ctest interrupt path deterministically via the test-only
+    # injection seam, with no OS signal, so it runs on every generator.  First
+    # run ctest normally so the postCTest hook runs and creates its marker file;
+    # remove it so its absence after the injected run proves that run's hook was
+    # skipped.
+    set(RunCMake_QUIET_ERROR 1)
+    run_cmake_command(${test}-warmup
+      ${CMAKE_CTEST_COMMAND} . -C Debug)
+    file(REMOVE ${v1}/postCTest.hook)
+
+    # Inject an interrupt (SIGINT == 2) via the undocumented test seam and run
+    # ctest again; ctest exits with an error status (cmCTest::TEST_ERRORS == 8)
+    # but writes the interrupted ctest snippet and skips the hook.
+    set(ENV{__CMAKE_INSTRUMENTATION_TEST_INTERRUPT} 2)
+    set(RunCMake_TEST_EXPECT_RESULT 8)
+    run_cmake_command(${test}-seam
+      ${CMAKE_CTEST_COMMAND} . -C Debug)
+    unset(RunCMake_TEST_EXPECT_RESULT)
+    unset(ENV{__CMAKE_INSTRUMENTATION_TEST_INTERRUPT})
+    unset(RunCMake_QUIET_ERROR)
+  endif()
+  if (ARGS_CTEST_INTERRUPT)
+    # Build just the interrupt helper so it exists for the interrupted run.
+    run_cmake_command(${test}-helper
+      ${CMAKE_COMMAND} --build . --config Debug --target InterruptBuild)
+    file(REMOVE ${v1}/postCTest.hook)
+    file(REMOVE_RECURSE ${RunCMake_TEST_BINARY_DIR}/ran)
+
+    set(helper_dir ${RunCMake_TEST_BINARY_DIR})
+    if (RunCMake_GENERATOR_IS_MULTI_CONFIG)
+      set(helper_dir ${helper_dir}/Debug)
+    endif()
+    set(helper ${helper_dir}/InterruptBuild${CMAKE_EXECUTABLE_SUFFIX})
+
+    # Interrupt a serial `ctest -j 1` a few seconds in, while the fast test has
+    # finished and a slow test is in-flight with others pending.  The
+    # instrumented ctest re-raises the signal, so the helper reports exit 42.
+    # Restrict to the ctest* fixture tests (the project's `test` needs `main`).
+    set(RunCMake_TEST_OUTPUT_MERGE 1)
+    set(RunCMake_QUIET_ERROR 1)
+    run_cmake_command(${test}-signal
+      ${helper} 4
+      ${CMAKE_CTEST_COMMAND} . -C Debug -j 1 -R ctest)
+    unset(RunCMake_QUIET_ERROR)
+    unset(RunCMake_TEST_OUTPUT_MERGE)
+
+    # Record which tests ran during the interrupted run so the check script can
+    # assert the pending tests were canceled.
+    if (EXISTS ${RunCMake_TEST_BINARY_DIR}/ran)
+      file(RENAME ${RunCMake_TEST_BINARY_DIR}/ran
+        ${RunCMake_TEST_BINARY_DIR}/ran-interrupt)
+    endif()
+  endif()
+  if (ARGS_CTEST_FAILOVER)
+    # Build just the interrupt helper so it exists for the interrupted run.
+    run_cmake_command(${test}-helper
+      ${CMAKE_COMMAND} --build . --config Debug --target InterruptBuild)
+    file(REMOVE ${v1}/postCTest.hook)
+    file(REMOVE_RECURSE ${RunCMake_TEST_BINARY_DIR}/ran)
+
+    set(helper_dir ${RunCMake_TEST_BINARY_DIR})
+    if (RunCMake_GENERATOR_IS_MULTI_CONFIG)
+      set(helper_dir ${helper_dir}/Debug)
+    endif()
+    set(helper ${helper_dir}/InterruptBuild${CMAKE_EXECUTABLE_SUFFIX})
+
+    # Phase 1: interrupt a serial `ctest -j 1` while a slow test is in-flight.
+    # The fast test finishes (checkpointed); the in-flight slow test is killed
+    # (deliberately not checkpointed) and the rest stay pending.  Restrict to
+    # the ctest* fixture tests (the project's `test` needs `main`).
+    set(RunCMake_TEST_OUTPUT_MERGE 1)
+    set(RunCMake_QUIET_ERROR 1)
+    run_cmake_command(${test}-signal
+      ${helper} 4
+      ${CMAKE_CTEST_COMMAND} . -C Debug -j 1 -R ctest)
+    if (EXISTS ${RunCMake_TEST_BINARY_DIR}/ran)
+      file(RENAME ${RunCMake_TEST_BINARY_DIR}/ran
+        ${RunCMake_TEST_BINARY_DIR}/ran-interrupt)
+    endif()
+
+    # The interrupted run left an un-indexed ctest snippet marked with
+    # interruptSignal.  The resuming run below re-indexes instrumentation, and
+    # the generic snippet validator rejects that field, so clear the snippet
+    # data first.  The `ctest -F` checkpoint lives under Testing/Temporary and
+    # is untouched.
+    file(REMOVE_RECURSE ${v1}/data)
+
+    # Phase 2: resume the interrupted test set with `ctest -F`.  It must skip
+    # the already-finished fast test and run the interrupted and pending slow
+    # tests (run in parallel so resume finishes promptly).
+    run_cmake_command(${test}-resume
+      ${CMAKE_CTEST_COMMAND} . -C Debug -F -j 4 -R ctest)
+    unset(RunCMake_QUIET_ERROR)
+    unset(RunCMake_TEST_OUTPUT_MERGE)
+    if (EXISTS ${RunCMake_TEST_BINARY_DIR}/ran)
+      file(RENAME ${RunCMake_TEST_BINARY_DIR}/ran
+        ${RunCMake_TEST_BINARY_DIR}/ran-resume)
+    endif()
+  endif()
   if (ARGS_MANUAL_HOOK)
     run_cmake_command(${test}-index ${CMAKE_CTEST_COMMAND} --collect-instrumentation .)
   endif()
@@ -345,6 +453,18 @@ if (INSTRUMENTATION_INTERRUPT_REAL)
     instrument(interrupt-install INSTALL_INTERRUPT
       CHECK_SCRIPT check-installation-interrupted.cmake
     )
+    # Interrupt a `ctest` run with a real OS signal, proving the scheduler stops
+    # launching pending tests, skips the hook, and preserves the `ctest -F`
+    # checkpoint so the interrupted test set can be resumed.
+    instrument(interrupt-test CTEST_INTERRUPT
+      CHECK_SCRIPT check-test-interrupted.cmake
+    )
+    # Interrupt a `ctest` run and then resume it with `ctest -F`, proving the
+    # checkpoint keeps the finished test (skipped on resume) but not the
+    # in-flight test killed by the interrupt (re-run on resume).
+    instrument(interrupt-test-failover CTEST_FAILOVER
+      CHECK_SCRIPT check-test-failover.cmake
+    )
   endif()
   return()
 endif()
@@ -567,6 +687,9 @@ instrument(interrupt-build INTERRUPT_SEAM
 instrument(interrupt-install BUILD INSTALL_SEAM
   CHECK_SCRIPT check-installation-interrupted.cmake
 )
+instrument(interrupt-test BUILD CTEST_SEAM
+  CHECK_SCRIPT check-test-interrupted.cmake
+)
 
 # Test make/ninja hooks
 if(RunCMake_GENERATOR STREQUAL "FASTBuild")
diff --git a/Tests/RunCMake/Instrumentation/check-test-failover.cmake b/Tests/RunCMake/Instrumentation/check-test-failover.cmake
new file mode 100644
index 0000000000..a723c2198d
--- /dev/null
+++ b/Tests/RunCMake/Instrumentation/check-test-failover.cmake
@@ -0,0 +1,33 @@
+include(${CMAKE_CURRENT_LIST_DIR}/json.cmake)
+
+# This checks a `ctest -F` resume of an interrupted test set.  The overall
+# ctest snippet and the postCTest hook are exercised by the seam and
+# interrupt-only cases; here the resuming run re-runs (and re-indexes) the
+# instrumentation, so only the resume behavior is asserted.
+
+set(ran_interrupt ${RunCMake_TEST_BINARY_DIR}/ran-interrupt)
+set(ran_resume ${RunCMake_TEST_BINARY_DIR}/ran-resume)
+
+if (NOT EXISTS ${ran_interrupt})
+  add_error("Expected the interrupted run to record which tests ran")
+elseif (NOT EXISTS ${ran_interrupt}/ctestFast)
+  add_error("ctestFast should have finished before the interrupt, but did not")
+endif()
+
+if (NOT EXISTS ${ran_resume})
+  add_error("Expected the `ctest -F` resume to record which tests ran")
+else ()
+  # Failover: `ctest -F` must skip the already-finished fast test (it was
+  # checkpointed) and re-run the interrupted and pending slow tests (the
+  # in-flight test killed by the interrupt was deliberately not checkpointed).
+  if (EXISTS ${ran_resume}/ctestFast)
+    add_error("ctestFast finished before the interrupt and should be skipped "
+      "by `ctest -F`, but it ran again")
+  endif()
+  foreach (n 1 2 3)
+    if (NOT EXISTS ${ran_resume}/ctestSlow${n})
+      add_error("ctestSlow${n} was not finished before the interrupt and must "
+        "run on `ctest -F` resume, but it did not")
+    endif()
+  endforeach()
+endif()
diff --git a/Tests/RunCMake/Instrumentation/check-test-interrupted.cmake b/Tests/RunCMake/Instrumentation/check-test-interrupted.cmake
new file mode 100644
index 0000000000..b0a5cbef74
--- /dev/null
+++ b/Tests/RunCMake/Instrumentation/check-test-interrupted.cmake
@@ -0,0 +1,25 @@
+include(${CMAKE_CURRENT_LIST_DIR}/json.cmake)
+
+# After an interrupted `ctest`, exactly one ctest snippet should be present,
+# marked with the interrupting signal, and the postCTest hook must have been
+# skipped.
+check_interrupted_snippet(ctest postCTest)
+
+# The real-signal case (CTEST_INTERRUPT) records which tests ran in a marker
+# directory.  The deterministic seam case runs no tests, so guard on the
+# directory's existence.
+set(ran_interrupt ${RunCMake_TEST_BINARY_DIR}/ran-interrupt)
+
+if (EXISTS ${ran_interrupt})
+  # Cancellation: the fast test finished but the pending slow tests must not all
+  # have started, proving the scheduler stopped launching tests on interrupt.
+  if (NOT EXISTS ${ran_interrupt}/ctestFast)
+    add_error("ctestFast should have run before the interrupt, but did not")
+  endif()
+  file(GLOB slow_ran LIST_DIRECTORIES false ${ran_interrupt}/ctestSlow*)
+  list(LENGTH slow_ran num_slow_ran)
+  if (num_slow_ran GREATER_EQUAL 3)
+    add_error("Expected some slow tests to remain pending on interrupt, "
+      "but all ${num_slow_ran} ran: ${slow_ran}")
+  endif()
+endif()
diff --git a/Tests/RunCMake/Instrumentation/interrupt-test-failover-signal-result.txt b/Tests/RunCMake/Instrumentation/interrupt-test-failover-signal-result.txt
new file mode 100644
index 0000000000..d81cc0710e
--- /dev/null
+++ b/Tests/RunCMake/Instrumentation/interrupt-test-failover-signal-result.txt
@@ -0,0 +1 @@
+42
diff --git a/Tests/RunCMake/Instrumentation/interrupt-test-signal-result.txt b/Tests/RunCMake/Instrumentation/interrupt-test-signal-result.txt
new file mode 100644
index 0000000000..d81cc0710e
--- /dev/null
+++ b/Tests/RunCMake/Instrumentation/interrupt-test-signal-result.txt
@@ -0,0 +1 @@
+42
diff --git a/Tests/RunCMake/Instrumentation/project/CMakeLists.txt b/Tests/RunCMake/Instrumentation/project/CMakeLists.txt
index 17d3c76703..e2dda8573f 100644
--- a/Tests/RunCMake/Instrumentation/project/CMakeLists.txt
+++ b/Tests/RunCMake/Instrumentation/project/CMakeLists.txt
@@ -89,3 +89,25 @@ if (INSTALL_INTERRUPT)
   add_subdirectory(installSlow2)
   add_subdirectory(installSlow3)
 endif()
+
+if (CTEST_INTERRUPT)
+  # A fast test plus several slow tests.  A high COST on the fast test makes it
+  # sort first (CTest orders by descending cost, and on a first run with no
+  # historical cost data the COST property is used), so with `ctest -j 1` the
+  # fast test finishes first -- recording a completed test in the checkpoint --
+  # and then one slow test is in-flight, with the remaining slow tests pending,
+  # when the interrupt arrives.  Each test touches a marker so the check script
+  # can observe which tests ran.  Dependencies are deliberately avoided: on a
+  # `ctest -F` resume the finished fast test is removed, which would otherwise
+  # leave its dependents blocked.  (InterruptBuild is provided by the
+  # INTERRUPT_BUILD_SRC block above, which is always enabled together with this.)
+  set(runtest "${CMAKE_CURRENT_SOURCE_DIR}/runtest.cmake")
+  add_test(NAME ctestFast COMMAND ${CMAKE_COMMAND}
+    -DMARKER=${CMAKE_BINARY_DIR}/ran/ctestFast -P ${runtest})
+  set_tests_properties(ctestFast PROPERTIES COST 100)
+  foreach (n 1 2 3)
+    add_test(NAME ctestSlow${n} COMMAND ${CMAKE_COMMAND}
+      -DMARKER=${CMAKE_BINARY_DIR}/ran/ctestSlow${n} -DSECONDS=10 -P ${runtest})
+    set_tests_properties(ctestSlow${n} PROPERTIES COST 1)
+  endforeach()
+endif()
diff --git a/Tests/RunCMake/Instrumentation/project/runtest.cmake b/Tests/RunCMake/Instrumentation/project/runtest.cmake
new file mode 100644
index 0000000000..711c82ea23
--- /dev/null
+++ b/Tests/RunCMake/Instrumentation/project/runtest.cmake
@@ -0,0 +1,16 @@
+# Test helper run as a CTest test command:
+#   cmake -DMARKER=<path> [-DSECONDS=<n>] -P runtest.cmake
+#
+# It records that the test started by touching MARKER, then optionally sleeps
+# for SECONDS.  The marker lets the interrupt tests observe exactly which tests
+# ran (and thus which pending tests were canceled, or which finished tests a
+# `ctest -F` resume skipped).
+cmake_minimum_required(VERSION 3.30)
+
+cmake_path(GET MARKER PARENT_PATH marker_dir)
+file(MAKE_DIRECTORY "${marker_dir}")
+file(TOUCH "${MARKER}")
+
+if (SECONDS)
+  execute_process(COMMAND "${CMAKE_COMMAND}" -E sleep "${SECONDS}")
+endif()
diff --git a/Tests/RunCMake/Instrumentation/query/interrupt-test-failover.json.in b/Tests/RunCMake/Instrumentation/query/interrupt-test-failover.json.in
new file mode 100644
index 0000000000..81477e6704
--- /dev/null
+++ b/Tests/RunCMake/Instrumentation/query/interrupt-test-failover.json.in
@@ -0,0 +1,5 @@
+{
+  "version": 1,
+  "hooks": ["postCTest"],
+  "callbacks": ["@GET_HOOK@"]
+}
diff --git a/Tests/RunCMake/Instrumentation/query/interrupt-test.json.in b/Tests/RunCMake/Instrumentation/query/interrupt-test.json.in
new file mode 100644
index 0000000000..81477e6704
--- /dev/null
+++ b/Tests/RunCMake/Instrumentation/query/interrupt-test.json.in
@@ -0,0 +1,5 @@
+{
+  "version": 1,
+  "hooks": ["postCTest"],
+  "callbacks": ["@GET_HOOK@"]
+}