diff --git a/railties/CHANGELOG.md b/railties/CHANGELOG.md
index 1d01c8d0e54cff5e60f9e7c0620a0a6f33ffdf19..d12a1f21f8814eb86e75497cd28f8760e00c2de3 100644
--- a/railties/CHANGELOG.md
+++ b/railties/CHANGELOG.md
@@ -1,3 +1,11 @@
+*   Make the application name snake cased when it contains spaces
+
+    The application name is used to fill the `database.yml` and
+    `session_store.rb` files ; previously, if the provided name
+    contained whitespaces, it led to unexpected names in these files.
+
+    *Robin Dupret*
+
 *   Added `--model-name` option to `ScaffoldControllerGenerator`.
 
     *yalab*
diff --git a/railties/lib/rails/generators/rails/app/app_generator.rb b/railties/lib/rails/generators/rails/app/app_generator.rb
index 92c876c83519a4fe61693c1cf743e6ba5d5b0dd3..db6b11abfa590d3d106611b216964328788ae247 100644
--- a/railties/lib/rails/generators/rails/app/app_generator.rb
+++ b/railties/lib/rails/generators/rails/app/app_generator.rb
@@ -239,7 +239,7 @@ def file(*args, &block)
       end
 
       def app_name
-        @app_name ||= (defined_app_const_base? ? defined_app_name : File.basename(destination_root)).tr(".", "_")
+        @app_name ||= (defined_app_const_base? ? defined_app_name : File.basename(destination_root)).tr('\\', '').tr(". ", "_")
       end
 
       def defined_app_name
diff --git a/railties/lib/rails/generators/testing/assertions.rb b/railties/lib/rails/generators/testing/assertions.rb
index 6267b2f2ee187a1e01ed9e424c97b5416f9b72b4..cc88e830dd007a1d2638128a394973c8fe356d3e 100644
--- a/railties/lib/rails/generators/testing/assertions.rb
+++ b/railties/lib/rails/generators/testing/assertions.rb
@@ -21,7 +21,7 @@ module Assertions
         #     end
         #   end
         def assert_file(relative, *contents)
-          absolute = File.expand_path(relative, destination_root)
+          absolute = File.expand_path(relative, destination_root).shellescape
           assert File.exists?(absolute), "Expected file #{relative.inspect} to exist, but does not"
 
           read = File.read(absolute) if block_given? || !contents.empty?
diff --git a/railties/test/generators/app_generator_test.rb b/railties/test/generators/app_generator_test.rb
index 2f0dfc7d3ee7192bb9b60381e6ea65e99b2bc135..24f01c878c80d24eafd3737ac600c2ceefcf4e08 100644
--- a/railties/test/generators/app_generator_test.rb
+++ b/railties/test/generators/app_generator_test.rb
@@ -367,6 +367,16 @@ def test_pretend_option
     assert_no_match(/run  bundle install/, output)
   end
 
+  def test_application_name_with_spaces
+    path = File.join(destination_root, "foo bar".shellescape)
+
+    # This also applies to MySQL apps but not with SQLite
+    run_generator [path, "-d", 'postgresql']
+
+    assert_file "foo bar/config/database.yml", /database: foo_bar_development/
+    assert_file "foo bar/config/initializers/session_store.rb", /key: '_foo_bar/
+  end
+
 protected
 
   def action(*args, &block)