diff --git a/src/vs/workbench/contrib/notebook/browser/media/notebook.css b/src/vs/workbench/contrib/notebook/browser/media/notebook.css
index ff74e5e1259..4bf9d923466 100644
--- a/src/vs/workbench/contrib/notebook/browser/media/notebook.css
+++ b/src/vs/workbench/contrib/notebook/browser/media/notebook.css
@@ -99,6 +99,11 @@
 	display: flex;
 }
 
+.monaco-workbench .notebookOverlay > .cell-list-container > .monaco-list > .monaco-scrollable-element > .monaco-list-rows > .monaco-list-row:not(.selected) .monaco-editor .lines-content .selected-text,
+.monaco-workbench .notebookOverlay > .cell-list-container > .monaco-list > .monaco-scrollable-element > .monaco-list-rows > .monaco-list-row:not(.selected) .monaco-editor .lines-content .selectionHighlight {
+	opacity: 0.33;
+}
+
 .monaco-workbench .notebookOverlay .notebook-content-widgets {
 	position: absolute;
 	top: 0;