diff --git a/compiler-rt/lib/fuzzer/tests/CMakeLists.txt b/compiler-rt/lib/fuzzer/tests/CMakeLists.txt
index cfb039c77d05..5b3e90641954 100644
--- a/compiler-rt/lib/fuzzer/tests/CMakeLists.txt
+++ b/compiler-rt/lib/fuzzer/tests/CMakeLists.txt
@@ -23,6 +23,10 @@ list(APPEND LIBFUZZER_UNITTEST_LINK_FLAGS --driver-mode=g++)
 if(WIN32)
   list(APPEND LIBFUZZER_UNITTEST_LINK_FLAGS -Wl,-defaultlib:libcmt,-defaultlib:oldnames)
 else()
+  if (APPLE)
+    list(APPEND LIBFUZZER_UNITTEST_CFLAGS -isysroot ${DARWIN_osx_SYSROOT})
+    list(APPEND LIBFUZZER_UNITTEST_LINK_FLAGS -isysroot ${DARWIN_osx_SYSROOT})
+  endif()
   list(APPEND LIBFUZZER_UNITTEST_LINK_FLAGS -lpthread)
 endif()