diff --git a/app/assets/javascripts/vue_shared/components/markdown/header.vue b/app/assets/javascripts/vue_shared/components/markdown/header.vue
index fe975112b609880b1263c1454b9e5657518c7432..f79c66514d2490b76672fdd642b9d955a54499e7 100644
--- a/app/assets/javascripts/vue_shared/components/markdown/header.vue
+++ b/app/assets/javascripts/vue_shared/components/markdown/header.vue
@@ -129,7 +129,7 @@ export default {
       <li :class="{ active: !previewMarkdown }" class="md-header-toolbar">
         <div class="d-inline-block">
           <toolbar-button tag="**" :button-title="__('Add bold text')" icon="bold" />
-          <toolbar-button tag="*" :button-title="__('Add italic text')" icon="italic" />
+          <toolbar-button tag="_" :button-title="__('Add italic text')" icon="italic" />
           <toolbar-button
             :prepend="true"
             :tag="tag"
diff --git a/app/views/shared/blob/_markdown_buttons.html.haml b/app/views/shared/blob/_markdown_buttons.html.haml
index 32fd732cda99dbb4d1595272a7e8ea5fd3ffefe4..d0719bf21fe3b24328360d6065433ccfe0e4258b 100644
--- a/app/views/shared/blob/_markdown_buttons.html.haml
+++ b/app/views/shared/blob/_markdown_buttons.html.haml
@@ -1,6 +1,6 @@
 .md-header-toolbar.active
   = markdown_toolbar_button({ icon: "bold", data: { "md-tag" => "**" }, title: _("Add bold text") })
-  = markdown_toolbar_button({ icon: "italic", data: { "md-tag" => "*" }, title: _("Add italic text") })
+  = markdown_toolbar_button({ icon: "italic", data: { "md-tag" => "_" }, title: _("Add italic text") })
   = markdown_toolbar_button({ icon: "quote", data: { "md-tag" => "> ", "md-prepend" => true }, title: _("Insert a quote") })
   = markdown_toolbar_button({ icon: "code", data: { "md-tag" => "`", "md-block" => "```" }, title: _("Insert code") })
   = markdown_toolbar_button({ icon: "link", data: { "md-tag" => "[{text}](url)", "md-select" => "url" }, title: _("Add a link") })
diff --git a/spec/features/issues/markdown_toolbar_spec.rb b/spec/features/issues/markdown_toolbar_spec.rb
index aab9d1026f9b233e64fb30ffae356129ffb0bf7f..6dc1cbfb2d77453c166e3141e23215f78b4e6a4a 100644
--- a/spec/features/issues/markdown_toolbar_spec.rb
+++ b/spec/features/issues/markdown_toolbar_spec.rb
@@ -36,6 +36,6 @@
 
     all('.toolbar-btn')[1].click
 
-    expect(find('#note-body')[:value]).to eq("test\n*underline*\n")
+    expect(find('#note-body')[:value]).to eq("test\n_underline_\n")
   end
 end