diff --git a/src/widgets/styles/qstylehelper_p.h b/src/widgets/styles/qstylehelper_p.h
index 98470ad1ced..43333e9e9d7 100644
--- a/src/widgets/styles/qstylehelper_p.h
+++ b/src/widgets/styles/qstylehelper_p.h
@@ -39,7 +39,7 @@ class QWindow;
 
 namespace QStyleHelper
 {
-    QString uniqueName(const QString &key, const QStyleOption *option, const QSize &size, qreal dpr);
+    Q_WIDGETS_EXPORT QString uniqueName(const QString &key, const QStyleOption *option, const QSize &size, qreal dpr);
 
     Q_WIDGETS_EXPORT qreal dpi(const QStyleOption *option);