diff --git a/templates/repo/diff/box.tmpl b/templates/repo/diff/box.tmpl
index 658022d94e93..a602a671a08e 100644
--- a/templates/repo/diff/box.tmpl
+++ b/templates/repo/diff/box.tmpl
@@ -104,7 +104,9 @@
 
 														</td>
 														<td class="lines-code lines-code-old halfwidth">
-															<a class="ui green button add-code-comment add-code-comment-left" data-path="{{$file.Name}}" data-side="left" data-idx="{{$line.LeftIdx}}">+</a>
+															{{if not (len $line.Comments)}}
+																<a class="ui green button add-code-comment add-code-comment-right" data-path="{{$file.Name}}" data-side="right" data-idx="{{$line.RightIdx}}">+</a>
+															{{end}}
 															<pre><code class="wrap {{if $highlightClass}}language-{{$highlightClass}}{{else}}nohighlight{{end}}">{{if $line.LeftIdx}}{{$section.GetComputedInlineDiffFor $line}}{{end}}</code></pre>
 														</td>
 														<td class="lines-num lines-num-new">
@@ -112,7 +114,9 @@
 														</td>
 
 														<td class="lines-code lines-code-new halfwidth">
-															<a class="ui green button add-code-comment add-code-comment-right" data-path="{{$file.Name}}" data-side="right" data-idx="{{$line.RightIdx}}">+</a>
+															{{if not (len $line.Comments)}}
+																<a class="ui green button add-code-comment add-code-comment-right" data-path="{{$file.Name}}" data-side="right" data-idx="{{$line.RightIdx}}">+</a>
+															{{end}}
 															<pre><code class="wrap {{if $highlightClass}}language-{{$highlightClass}}{{else}}nohighlight{{end}}">{{if $line.RightIdx}}{{$section.GetComputedInlineDiffFor $line}}{{end}}</code></pre>
 														</td>
 													</tr>
diff --git a/templates/repo/diff/section_unified.tmpl b/templates/repo/diff/section_unified.tmpl
index b710532975b9..8db154bd5716 100644
--- a/templates/repo/diff/section_unified.tmpl
+++ b/templates/repo/diff/section_unified.tmpl
@@ -16,7 +16,9 @@
 			</td>
 			{{end}}
 			<td class="lines-code {{if (not $line.RightIdx)}}lines-code-old{{end}}">
-				<a class="ui green button add-code-comment add-code-comment-{{if $line.RightIdx}}right{{else}}left{{end}}" data-path="{{$file.Name}}" data-side="{{if $line.RightIdx}}right{{else}}left{{end}}" data-idx="{{if $line.RightIdx}}{{$line.RightIdx}}{{else}}{{$line.LeftIdx}}{{end}}">+</a>
+				{{if not (len $line.Comments)}}
+					<a class="ui green button add-code-comment add-code-comment-{{if $line.RightIdx}}right{{else}}left{{end}}" data-path="{{$file.Name}}" data-side="{{if $line.RightIdx}}right{{else}}left{{end}}" data-idx="{{if $line.RightIdx}}{{$line.RightIdx}}{{else}}{{$line.LeftIdx}}{{end}}">+</a>
+				{{end}}
 				<pre><code class="wrap {{if $highlightClass}}language-{{$highlightClass}}{{else}}nohighlight{{end}}">{{$section.GetComputedInlineDiffFor $line}}</code></pre>
 			</td>
 		</tr>