diff --git a/lld/COFF/Driver.cpp b/lld/COFF/Driver.cpp
--- a/lld/COFF/Driver.cpp
+++ b/lld/COFF/Driver.cpp
@@ -473,7 +473,7 @@
   }
 
   if (path.endswith_insensitive(".lib"))
-    visitedLibs.insert(std::string(sys::path::filename(path)));
+    visitedLibs.insert(std::string(sys::path::filename(path).lower()));
   return path;
 }
 
diff --git a/lld/test/COFF/nodefaultlib.test b/lld/test/COFF/nodefaultlib.test
--- a/lld/test/COFF/nodefaultlib.test
+++ b/lld/test/COFF/nodefaultlib.test
@@ -36,3 +36,11 @@
 
 UPPERCASE-NOT: OLDNAMES
 UPPERCASE-NOT: LIBCMT
+
+# RUN: mv %T/std64.lib %T/STD64.lib
+# RUN: lld-link %T/STD64.lib /out:%t.exe /entry:main \
+# RUN:   /subsystem:console %T/hello64.obj /defaultlib:STD64.lib \
+# RUN:   /verbose 2>&1 | FileCheck -check-prefix=CHECK4 %s
+
+CHECK4: Reading {{.*}}/STD64.lib
+CHECK4-NOT: could not open 'STD64.lib'