diff --git a/actionpack/CHANGELOG.md b/actionpack/CHANGELOG.md
index 86bee63549d0d..f1eb9e84f6fe8 100644
--- a/actionpack/CHANGELOG.md
+++ b/actionpack/CHANGELOG.md
@@ -5,6 +5,23 @@
 
 ## Rails 3.2.13 (Feb 17, 2013) ##
 
+*   Fix incorrectly appended square brackets to a multiple select box
+    if an explicit name has been given and it already ends with "[]".
+
+    Before:
+
+        select(:category, [], {}, multiple: true, name: "post[category][]")
+        # => <select name="post[category][][]" ...>
+
+    After:
+
+        select(:category, [], {}, multiple: true, name: "post[category][]")
+        # => <select name="post[category][]" ...>
+
+    Backport #9616.
+
+    *Olek Janiszewski*
+
 *   Determine the controller#action from only the matched path when using the
     shorthand syntax. Previously the complete path was used, which led
     to problems with nesting (scopes and namespaces).
diff --git a/actionpack/lib/action_view/helpers/form_helper.rb b/actionpack/lib/action_view/helpers/form_helper.rb
index 7df74d96fb920..920dc3f794341 100644
--- a/actionpack/lib/action_view/helpers/form_helper.rb
+++ b/actionpack/lib/action_view/helpers/form_helper.rb
@@ -1207,7 +1207,7 @@ def add_default_name_and_id(options)
             options["id"] = options.fetch("id"){ tag_id }
           end
 
-          options["name"] += "[]" if options["multiple"]
+          options["name"] += "[]" if options["multiple"] && !options["name"].ends_with?("[]")
           options["id"] = [options.delete('namespace'), options["id"]].compact.join("_").presence
         end
 
diff --git a/actionpack/test/template/form_options_helper_test.rb b/actionpack/test/template/form_options_helper_test.rb
index 3009fa53304f8..72c2609a48fd2 100644
--- a/actionpack/test/template/form_options_helper_test.rb
+++ b/actionpack/test/template/form_options_helper_test.rb
@@ -515,6 +515,14 @@ def test_select_with_multiple_to_add_hidden_input
     )
   end
 
+  def test_select_with_multiple_and_with_explicit_name_ending_with_brackets
+    output_buffer =  select(:post, :category, "", {}, :multiple => true, :name => 'post[category][]')
+    assert_dom_equal(
+      "<input type=\"hidden\" name=\"post[category][]\" value=\"\"/><select multiple=\"multiple\" id=\"post_category\" name=\"post[category][]\"></select>",
+      output_buffer
+    )
+  end
+
   def test_select_with_multiple_and_disabled_to_add_disabled_hidden_input
     output_buffer =  select(:post, :category, "", {}, :multiple => true, :disabled => true)
     assert_dom_equal(