diff --git a/src/vcpkg-test/system.process.cpp b/src/vcpkg-test/system.process.cpp
index 58e9f6db61..f4489a43c6 100644
--- a/src/vcpkg-test/system.process.cpp
+++ b/src/vcpkg-test/system.process.cpp
@@ -2,6 +2,10 @@
 
 #include <vcpkg/base/system.process.h>
 
+#ifndef _WIN32
+#include <sys/wait.h>
+#endif
+
 using namespace vcpkg;
 
 TEST_CASE ("captures-output", "[system.process]")