diff --git a/taglib/toolkit/tbytevector.h b/taglib/toolkit/tbytevector.h
index bb856070..5533d13e 100644
--- a/taglib/toolkit/tbytevector.h
+++ b/taglib/toolkit/tbytevector.h
@@ -26,6 +26,7 @@
 #include "taglib_export.h"
 
 #include <vector>
+#include <ostream>
 
 namespace TagLib {
 
diff --git a/taglib/toolkit/tstring.h b/taglib/toolkit/tstring.h
index e9e3eedd..8bf5d961 100644
--- a/taglib/toolkit/tstring.h
+++ b/taglib/toolkit/tstring.h
@@ -27,6 +27,7 @@
 #include "tbytevector.h"
 
 #include <string>
+#include <ostream>
 
 /*!
  * \relates TagLib::String