diff --git a/resources/themes/Blend of Gray/style.qss b/resources/themes/Blend of Gray/style.qss
index 18562c6f982..02180df5d3e 100644
--- a/resources/themes/Blend of Gray/style.qss	
+++ b/resources/themes/Blend of Gray/style.qss	
@@ -761,6 +761,10 @@ QToolButton[autoRaise=false]:focus:!pressed {
     border:1px solid @focus;
 }
 
+QSlider::handle:horizontal:focus, QSlider::handle:vertical:focus {
+    border: 1px solid @focus;
+}
+
 /* ==================================================================================== */
 /* QGIS-SPECIFIC TWEAKS                                                                 */
 /* ==================================================================================== */
diff --git a/resources/themes/Night Mapping/style.qss b/resources/themes/Night Mapping/style.qss
index 7d59f639231..d75e5dcc0b8 100644
--- a/resources/themes/Night Mapping/style.qss	
+++ b/resources/themes/Night Mapping/style.qss	
@@ -772,6 +772,10 @@ QToolButton[autoRaise=false]:focus:!pressed {
     border:1px solid @focusdark;
 }
 
+QSlider::handle:horizontal:focus, QSlider::handle:vertical:focus {
+    border: 1px solid @focus;
+}
+
 /* ==================================================================================== */
 /* QGIS-SPECIFIC TWEAKS                                                                 */
 /* ==================================================================================== */