diff --git a/cmd/frontend/graphqlbackend/file.go b/cmd/frontend/graphqlbackend/file.go
index 745ba910fb433..261544367f2ee 100644
--- a/cmd/frontend/graphqlbackend/file.go
+++ b/cmd/frontend/graphqlbackend/file.go
@@ -64,7 +64,7 @@ func (*schemaResolver) HighlightCode(ctx context.Context, args *struct {
 }) (string, error) {
 	language := highlight.SyntectLanguageMap[strings.ToLower(args.FuzzyLanguage)]
 	filePath := "file." + language
-	html, _, err := highlight.Code(ctx, []byte(args.Code), filePath, args.DisableTimeout, args.IsLightTheme)
+	html, _, err := highlight.Code(ctx, []byte(args.Code), filePath, args.DisableTimeout, args.IsLightTheme, false)
 	if err != nil {
 		return args.Code, err
 	}
@@ -110,7 +110,8 @@ func (r *gitTreeEntryResolver) Highlight(ctx context.Context, args *struct {
 		html   template.HTML
 		result = &highlightedFileResolver{}
 	)
-	html, result.aborted, err = highlight.Code(ctx, content, r.path, args.DisableTimeout, args.IsLightTheme)
+	simulateTimeout := r.commit.repo.repo.Name == "github.com/sourcegraph/AlwaysHighlightTimeoutTest"
+	html, result.aborted, err = highlight.Code(ctx, content, r.path, args.DisableTimeout, args.IsLightTheme, simulateTimeout)
 	if err != nil {
 		return nil, err
 	}
diff --git a/cmd/frontend/internal/pkg/discussions/format.go b/cmd/frontend/internal/pkg/discussions/format.go
index abd76b3bee30f..2d2b9a6ea4a17 100644
--- a/cmd/frontend/internal/pkg/discussions/format.go
+++ b/cmd/frontend/internal/pkg/discussions/format.go
@@ -78,7 +78,7 @@ func formatTargetRepoLinesHTML(ctx context.Context, tr *types.DiscussionThreadTa
 		// contents along here.
 		isLightTheme := false
 		disableTimeout := false
-		html, _, err := highlight.Code(ctx, []byte(code), *tr.Path, disableTimeout, isLightTheme)
+		html, _, err := highlight.Code(ctx, []byte(code), *tr.Path, disableTimeout, isLightTheme, false)
 		if err != nil {
 			return err
 		}
diff --git a/pkg/highlight/highlight.go b/pkg/highlight/highlight.go
index 1348c39c352ba..9ae6d8011a59d 100644
--- a/pkg/highlight/highlight.go
+++ b/pkg/highlight/highlight.go
@@ -43,12 +43,15 @@ func IsBinary(content []byte) bool {
 //
 // The returned boolean represents whether or not highlighting was aborted due
 // to timeout. In this scenario, a plain text table is returned.
-func Code(ctx context.Context, content []byte, filepath string, disableTimeout bool, isLightTheme bool) (template.HTML, bool, error) {
+func Code(ctx context.Context, content []byte, filepath string, disableTimeout bool, isLightTheme bool, simulateTimeout bool) (template.HTML, bool, error) {
 	if !disableTimeout {
 		var cancel func()
 		ctx, cancel = context.WithTimeout(ctx, 3*time.Second)
 		defer cancel()
 	}
+	if simulateTimeout {
+		time.Sleep(4 * time.Second)
+	}
 
 	// Never pass binary files to the syntax highlighter.
 	if IsBinary(content) {