diff --git a/src/shell/leandoc.cpp b/src/shell/leandoc.cpp
index a8dd077609..d9ea511380 100644
--- a/src/shell/leandoc.cpp
+++ b/src/shell/leandoc.cpp
@@ -4,6 +4,7 @@ Released under Apache 2.0 license as described in the file LICENSE.
 
 Author: Leonardo de Moura
 */
+#include <string>
 #include <iostream>
 #include "kernel/inductive/inductive.h"
 #include "kernel/quotient/quotient.h"