diff --git a/README.rst b/README.rst
index 07eeba29..46c8f232 100644
--- a/README.rst
+++ b/README.rst
@@ -91,6 +91,8 @@ An object of any user-defined type for which there is an overloaded
 
 .. code:: c++
 
+    #include "fmt/ostream.h"
+
     class Date {
       int year_, month_, day_;
      public: