diff --git a/folly/experimental/symbolizer/Elf.cpp b/folly/experimental/symbolizer/Elf.cpp
index 6a7f74fa470..1402c1414da 100644
--- a/folly/experimental/symbolizer/Elf.cpp
+++ b/folly/experimental/symbolizer/Elf.cpp
@@ -16,6 +16,7 @@
 
 #include <folly/experimental/symbolizer/Elf.h>
 
+#include <unistd.h>
 #include <fcntl.h>
 #include <sys/stat.h>
 #include <sys/types.h>