diff --git a/lldb/packages/Python/lldbsuite/test/dotest.py b/lldb/packages/Python/lldbsuite/test/dotest.py
index 2966ac04227cb..1d474a2180d22 100644
--- a/lldb/packages/Python/lldbsuite/test/dotest.py
+++ b/lldb/packages/Python/lldbsuite/test/dotest.py
@@ -789,6 +789,10 @@ def canRunLibcxxTests():
         return True, "libc++ always present"
 
     if platform == "linux":
+        if not configuration.libcxx_include_dir or not configuration.libcxx_library_dir:
+            return False, "API tests require a locally built libc++."
+
+        # Make sure -stdlib=libc++ works since that's how the tests will be built.
         with temp_file.OnDiskTempFile() as f:
             cmd = [configuration.compiler, "-xc++", "-stdlib=libc++", "-o", f.path, "-"]
             p = subprocess.Popen(