diff --git a/AK/String.cpp b/AK/String.cpp
index 0be8c0fd995..ab7f3dbcc0e 100644
--- a/AK/String.cpp
+++ b/AK/String.cpp
@@ -36,10 +36,6 @@
 #    include <inttypes.h>
 #endif
 
-#ifdef KERNEL
-extern "C" char* strstr(const char* haystack, const char* needle);
-#endif
-
 namespace AK {
 
 String::String(const StringView& view)