diff --git a/folly/experimental/symbolizer/Elf.cpp b/folly/experimental/symbolizer/Elf.cpp
index 6a7f74fa4..33b44b4dd 100644
--- a/folly/experimental/symbolizer/Elf.cpp
+++ b/folly/experimental/symbolizer/Elf.cpp
@@ -21,6 +21,7 @@
 #include <sys/types.h>
 #include <cstring>
 #include <string>
+#include <unistd.h>
 
 #include <glog/logging.h>