diff --git a/libcxx/test/lit.cfg.py b/libcxx/test/lit.cfg.py
index ea4a9a75b4fdb8..bb055268774790 100644
--- a/libcxx/test/lit.cfg.py
+++ b/libcxx/test/lit.cfg.py
@@ -7,5 +7,6 @@
 lit_config.fatal(
     "You seem to be running Lit directly -- you should be running Lit through "
     "<build>/bin/llvm-lit, which will ensure that the right Lit configuration "
-    "file is used."
+    "file is used. See https://libcxx.llvm.org/TestingLibcxx.html#usage for "
+    "how to run the libc++ tests."
 )
diff --git a/libcxxabi/test/lit.cfg.py b/libcxxabi/test/lit.cfg.py
index ea4a9a75b4fdb8..fb36c8d4aaa32c 100644
--- a/libcxxabi/test/lit.cfg.py
+++ b/libcxxabi/test/lit.cfg.py
@@ -7,5 +7,6 @@
 lit_config.fatal(
     "You seem to be running Lit directly -- you should be running Lit through "
     "<build>/bin/llvm-lit, which will ensure that the right Lit configuration "
-    "file is used."
+    "file is used. See https://libcxx.llvm.org/TestingLibcxx.html#usage for "
+    "how to run the libc++abi tests."
 )
diff --git a/libunwind/test/lit.cfg.py b/libunwind/test/lit.cfg.py
index ea4a9a75b4fdb8..51e85e489db01f 100644
--- a/libunwind/test/lit.cfg.py
+++ b/libunwind/test/lit.cfg.py
@@ -7,5 +7,6 @@
 lit_config.fatal(
     "You seem to be running Lit directly -- you should be running Lit through "
     "<build>/bin/llvm-lit, which will ensure that the right Lit configuration "
-    "file is used."
+    "file is used. See https://libcxx.llvm.org/TestingLibcxx.html#usage for "
+    "how to run the libunwind tests."
 )