diff --git a/subsys/testsuite/ztest/CMakeLists.txt b/subsys/testsuite/ztest/CMakeLists.txt
index c9c9332898581f..a0cf1615159980 100644
--- a/subsys/testsuite/ztest/CMakeLists.txt
+++ b/subsys/testsuite/ztest/CMakeLists.txt
@@ -24,7 +24,7 @@ zephyr_library_sources_ifdef(CONFIG_ZTEST_MOCKING  src/ztest_mock.c)
 zephyr_library_sources_ifdef(CONFIG_ZTRESS         src/ztress.c)
 
 
-if(CONFIG_ARCH_POSIX)
+if(CONFIG_ARCH_POSIX AND CONFIG_EXTERNAL_LIBC)
   zephyr_library_sources_ifdef(CONFIG_ZTEST_NEW_API src/ztest_posix.c)
 else()
   zephyr_library_sources_ifdef(CONFIG_ZTEST_NEW_API src/ztest_defaults.c)