diff --git a/Userland/Libraries/LibELF/Validation.cpp b/Userland/Libraries/LibELF/Validation.cpp
index d334777fdf..83880b0f94 100644
--- a/Userland/Libraries/LibELF/Validation.cpp
+++ b/Userland/Libraries/LibELF/Validation.cpp
@@ -11,6 +11,7 @@
 #include <LibC/elf.h>
 #include <LibELF/Validation.h>
 #include <limits.h>
+#include <pthread.h>
 
 namespace ELF {