diff --git a/actionpack/lib/action_dispatch/routing/mapper.rb b/actionpack/lib/action_dispatch/routing/mapper.rb
index 2d2073de9a..08560ccf7d 100644
--- a/actionpack/lib/action_dispatch/routing/mapper.rb
+++ b/actionpack/lib/action_dispatch/routing/mapper.rb
@@ -1402,6 +1402,8 @@ module ActionDispatch
         #   as a comment on a blog post like <tt>/posts/a-long-permalink/comments/1234</tt>
         #   to be shortened to just <tt>/comments/1234</tt>.
         #
+        #   Set shallow: false on a child resource to ignore a parent's shallow parameter.
+        #
         # [:shallow_path]
         #   Prefixes nested shallow routes with the specified path.
         #
@@ -1672,7 +1674,8 @@ module ActionDispatch
               return true
             end
 
-            if options.delete(:shallow)
+            if options[:shallow]
+              options.delete(:shallow)
               shallow do
                 send(method, resources.pop, options, &block)
               end
diff --git a/actionpack/test/dispatch/routing_test.rb b/actionpack/test/dispatch/routing_test.rb
index 4645ba476f..de0c9f3460 100644
--- a/actionpack/test/dispatch/routing_test.rb
+++ b/actionpack/test/dispatch/routing_test.rb
@@ -2200,6 +2200,37 @@ class TestRoutingMapper < ActionDispatch::IntegrationTest
     assert_equal "cards#destroy", @response.body
   end
 
+  def test_shallow_false_inside_nested_shallow_resource
+    draw do
+      resources :blogs, shallow: true do
+        resources :posts do
+          resources :comments, shallow: false
+          resources :tags
+        end
+      end
+    end
+
+    get '/posts/1/comments'
+    assert_equal 'comments#index', @response.body
+    assert_equal '/posts/1/comments', post_comments_path('1')
+
+    get '/posts/1/comments/new'
+    assert_equal 'comments#new', @response.body
+    assert_equal '/posts/1/comments/new', new_post_comment_path('1')
+
+    get '/posts/1/comments/2'
+    assert_equal 'comments#show', @response.body
+    assert_equal '/posts/1/comments/2', post_comment_path('1', '2')
+
+    get '/posts/1/comments/2/edit'
+    assert_equal 'comments#edit', @response.body
+    assert_equal '/posts/1/comments/2/edit', edit_post_comment_path('1', '2')
+
+    get '/tags/3'
+    assert_equal 'tags#show', @response.body
+    assert_equal '/tags/3', tag_path('3')
+  end
+
   def test_shallow_deeply_nested_resources
     draw do
       resources :blogs do