diff --git a/src/corelib/mimetypes/qmimedatabase_p.h b/src/corelib/mimetypes/qmimedatabase_p.h
index 21669328db..b1e747c62e 100644
--- a/src/corelib/mimetypes/qmimedatabase_p.h
+++ b/src/corelib/mimetypes/qmimedatabase_p.h
@@ -54,6 +54,7 @@
 
 QT_BEGIN_NAMESPACE
 
+class QIODevice;
 class QMimeDatabase;
 class QMimeProviderBase;