diff --git a/app/views/shared/issuable/form/_branch_chooser.html.haml b/app/views/shared/issuable/form/_branch_chooser.html.haml
index a425f5f810e68bb400e837d9d5633ed51e84def6..70e931ac164e7afcb756a13717401cd6c6149b46 100644
--- a/app/views/shared/issuable/form/_branch_chooser.html.haml
+++ b/app/views/shared/issuable/form/_branch_chooser.html.haml
@@ -6,6 +6,17 @@
 
 - source_title, target_title = format_mr_branch_names(@merge_request)
 
+- vis010 = _('This merge request is from a private project to an internal project.')
+- vis020 = _('This merge request is from a private project to a public project.')
+- vis1020 = _('This merge request is from an internal project to a public project.')
+- i18n = { '010' => vis010, '020' => vis020, '1020' => vis1020 }
+
+- source_level = @merge_request.source_project.visibility_level
+- source_visibility = @merge_request.source_project.visibility
+- target_level = @merge_request.target_project.visibility_level
+
+- visibilityMismatchString = i18n["#{source_level}#{target_level}"]
+
 .form-group.row.d-flex.gl-px-5.branch-selector
   .align-self-center
     %span
@@ -24,4 +35,12 @@
       = form.hidden_field(:target_branch,
         { class: 'target_branch js-target-branch-select ref-name mw-xl',
           data: { placeholder: _('Select branch'), endpoint: refs_project_path(@project, sort: 'updated_desc', find: 'branches') }})
+
+- if source_level < target_level
+  .gl-alert.gl-alert-warning.gl-mt-4
+    = sprite_icon('warning', css_class: 'gl-icon gl-alert-icon gl-alert-icon-no-title')
+    .gl-alert-body
+      = visibilityMismatchString
+      %br
+      = _('Review the target project before submitting to avoid exposing %{source} changes.') % { source: source_visibility }
 %hr
diff --git a/changelogs/unreleased/feature-visibility-mismatch-warning.yml b/changelogs/unreleased/feature-visibility-mismatch-warning.yml
new file mode 100644
index 0000000000000000000000000000000000000000..a7c24a737f42974e0857d48338ae22e568e354b2
--- /dev/null
+++ b/changelogs/unreleased/feature-visibility-mismatch-warning.yml
@@ -0,0 +1,5 @@
+---
+title: Add visibility mismatch warning to the branch chooser
+merge_request: 51671
+author:
+type: changed
diff --git a/locale/gitlab.pot b/locale/gitlab.pot
index 0e177b97ddb2cb7dbd2c2875e1066735b8ee295d..dbae8e69668dd54a0918406ec7943386f0af5fe0 100644
--- a/locale/gitlab.pot
+++ b/locale/gitlab.pot
@@ -24337,6 +24337,9 @@ msgstr ""
 msgid "Review the process for configuring service providers in your identity provider — in this case, GitLab is the \"service provider\" or \"relying party\"."
 msgstr ""
 
+msgid "Review the target project before submitting to avoid exposing %{source} changes."
+msgstr ""
+
 msgid "Review time"
 msgstr ""
 
@@ -29015,6 +29018,15 @@ msgstr ""
 msgid "This merge request is closed. To apply this suggestion, edit this file directly."
 msgstr ""
 
+msgid "This merge request is from a private project to a public project."
+msgstr ""
+
+msgid "This merge request is from a private project to an internal project."
+msgstr ""
+
+msgid "This merge request is from an internal project to a public project."
+msgstr ""
+
 msgid "This merge request is locked."
 msgstr ""