diff --git a/options/locale/locale_en-US.json b/options/locale/locale_en-US.json
index d6c733b50b..b06cd7e715 100644
--- a/options/locale/locale_en-US.json
+++ b/options/locale/locale_en-US.json
@@ -1197,7 +1197,8 @@
   "repo.file.title": "%s at %s",
   "repo.file_raw": "Raw",
   "repo.file_history": "History",
-  "repo.file_view_source": "View Source",
+  "repo.file_view_source": "Source",
+  "repo.file_view_preview": "Preview",
   "repo.file_view_rendered": "View Rendered",
   "repo.file_view_raw": "View Raw",
   "repo.file_permalink": "Permalink",
diff --git a/routers/web/repo/view_file.go b/routers/web/repo/view_file.go
index a066df4067..029d74de9a 100644
--- a/routers/web/repo/view_file.go
+++ b/routers/web/repo/view_file.go
@@ -57,7 +57,15 @@ func prepareFileViewLfsAttrs(ctx *context.Context) (*attribute.Attributes, bool)
 	return attrs, true
 }
 
+func isHTMLTreePath(treePath string) bool {
+	lower := strings.ToLower(treePath)
+	return strings.HasSuffix(lower, ".html") || strings.HasSuffix(lower, ".htm")
+}
+
 func handleFileViewRenderMarkup(ctx *context.Context, prefetchBuf []byte, utf8Reader io.Reader) bool {
+	if isHTMLTreePath(ctx.Repo.TreePath) {
+		return false // HTML uses dedicated preview handler, not the markup engine
+	}
 	rctx := renderhelper.NewRenderContextRepoFile(ctx, ctx.Repo.Repository, renderhelper.RepoFileOptions{
 		CurrentRefPath:  ctx.Repo.RefTypeNameSubURL(),
 		CurrentTreePath: path.Dir(ctx.Repo.TreePath),
@@ -92,6 +100,9 @@ func handleFileViewRenderMarkup(ctx *context.Context, prefetchBuf []byte, utf8Re
 }
 
 func handleFileViewRenderSource(ctx *context.Context, attrs *attribute.Attributes, fInfo *fileInfo, utf8Reader io.Reader) bool {
+	if isHTMLTreePath(ctx.Repo.TreePath) && ctx.FormString("display") != "source" {
+		return false // default HTML files to iframe preview, not line-numbered source
+	}
 	filename := ctx.Repo.TreePath
 	if ctx.FormString("display") == "rendered" || !fInfo.st.IsRepresentableAsText() {
 		return false
@@ -154,8 +165,7 @@ func handleFileViewRenderImage(ctx *context.Context, fInfo *fileInfo, prefetchBu
 }
 
 func handleFileViewRenderHTML(ctx *context.Context, fInfo *fileInfo) bool {
-	lower := strings.ToLower(ctx.Repo.TreePath)
-	if !strings.HasSuffix(lower, ".html") && !strings.HasSuffix(lower, ".htm") {
+	if !isHTMLTreePath(ctx.Repo.TreePath) {
 		return false
 	}
 	// Allow toggling to source view
@@ -181,6 +191,10 @@ func prepareFileView(ctx *context.Context, entry *git.TreeEntry) {
 	ctx.Data["FileIsSymlink"] = entry.IsLink()
 	ctx.Data["FileTreePath"] = ctx.Repo.TreePath
 	ctx.Data["RawFileLink"] = ctx.Repo.RepoLink + "/raw/" + ctx.Repo.RefTypeNameSubURL() + "/" + util.PathEscapeSegments(ctx.Repo.TreePath)
+	if isHTMLTreePath(ctx.Repo.TreePath) {
+		ctx.Data["IsHTMLFile"] = true
+		ctx.Data["HasSourceRenderedToggle"] = true
+	}
 
 	if ctx.Repo.TreePath == ".editorconfig" {
 		_, editorconfigWarning, editorconfigErr := ctx.Repo.GetEditorconfig(ctx.Repo.Commit)
diff --git a/templates/repo/view_file.tmpl b/templates/repo/view_file.tmpl
index 73f1c761e2..287983ae96 100644
--- a/templates/repo/view_file.tmpl
+++ b/templates/repo/view_file.tmpl
@@ -35,6 +35,12 @@
 			{{end}}
 		</div>
 		<div class="file-header-right file-actions flex-text-block tw-flex-wrap">
+			{{if .IsHTMLFile}}
+				<div class="ui mini buttons tw-mr-1">
+					<a href="?display=rendered" class="ui mini basic button {{if not .IsDisplayingSource}}active{{end}}">{{ctx.Locale.Tr "repo.file_view_preview"}}</a>
+					<a href="?display=source" class="ui mini basic button {{if .IsDisplayingSource}}active{{end}}">{{ctx.Locale.Tr "repo.file_view_source"}}</a>
+				</div>
+			{{end}}
 			{{/* this componment is also controlled by frontend plugin renders */}}
 			<div class="ui compact icon buttons file-view-toggle-buttons {{Iif .HasSourceRenderedToggle "" "tw-hidden"}}">
 				{{if .IsRepresentableAsText}}