diff --git a/Tests/CMakeLists.txt b/Tests/CMakeLists.txt
index 05570357d..32beffa80 100644
--- a/Tests/CMakeLists.txt
+++ b/Tests/CMakeLists.txt
@@ -2415,6 +2415,7 @@ ${CMake_BINARY_DIR}/bin/cmake -DDIR=dev -P ${CMake_SOURCE_DIR}/Utilities/Release
   set_tests_properties(CTestCoverageCollectGCOV PROPERTIES
     PASS_REGULAR_EXPRESSION
     "PASSED with correct output.*Testing/CoverageInfo/main.cpp.gcov")
+  set_property(TEST CTestCoverageCollectGCOV PROPERTY ENVIRONMENT CTEST_PARALLEL_LEVEL=)
 
   configure_file(
     "${CMake_SOURCE_DIR}/Tests/CTestTestEmptyBinaryDirectory/test.cmake.in"
@@ -2714,6 +2715,7 @@ ${CMake_BINARY_DIR}/bin/cmake -DDIR=dev -P ${CMake_SOURCE_DIR}/Utilities/Release
     )
   set_tests_properties(CTestTestSkipReturnCode PROPERTIES
     PASS_REGULAR_EXPRESSION "CMakeV1 \\.* +Passed.*CMakeV2 \\.+\\*+Skipped")
+  set_property(TEST CTestTestSkipReturnCode PROPERTY ENVIRONMENT CTEST_PARALLEL_LEVEL=)
 
   ADD_TEST_MACRO(CTestTestSerialInDepends ${CMAKE_CTEST_COMMAND} -j 4
     --output-on-failure -C "\${CTestTest_CONFIG}")
diff --git a/Tests/RunCMake/ctest_memcheck/RunCMakeTest.cmake b/Tests/RunCMake/ctest_memcheck/RunCMakeTest.cmake
index 6c96a265b..5ad65110a 100644
--- a/Tests/RunCMake/ctest_memcheck/RunCMakeTest.cmake
+++ b/Tests/RunCMake/ctest_memcheck/RunCMakeTest.cmake
@@ -4,6 +4,8 @@ set(SITE test-site)
 set(BUILDNAME test-build)
 set(COVERAGE_COMMAND "")
 
+unset(ENV{CTEST_PARALLEL_LEVEL})
+
 function(run_mc_test CASE_NAME CHECKER_COMMAND)
   run_ctest(${CASE_NAME} ${ARGN})
 endfunction()