diff --git a/folly/CancellationToken-inl.h b/folly/CancellationToken-inl.h
index e50dc88a7f3..72f7f9aa803 100644
--- a/folly/CancellationToken-inl.h
+++ b/folly/CancellationToken-inl.h
@@ -15,6 +15,7 @@
  */
 
 #include <algorithm>
+#include <array>
 #include <cstdint>
 #include <limits>
 #include <tuple>