diff --git a/manifests/init.pp b/manifests/init.pp
index f9afb534..85b854f0 100644
--- a/manifests/init.pp
+++ b/manifests/init.pp
@@ -388,6 +388,17 @@
 #    (optional) Enable the password field while launching a Heat stack.
 #    Defaults to true
 #
+#  [*customization_module*]
+#    (optional) Horizon has a global override mechanism available to perform
+#    customizations. This adds a key - customization_module - to HORIZON_CONFIG
+#    dictionary in local_settings.py. The value should be a string with the
+#    path to your module containing modifications in dotted python path
+#    notation.
+#    Defaults to undef
+#
+#    Example:
+#      customization_module => "my_project.overrides"
+#
 # === DEPRECATED group/name
 #
 #  [*fqdn*]
@@ -498,6 +509,7 @@ class horizon(
   $password_validator                  = undef,
   $password_validator_help             = undef,
   $enable_user_pass                    = true,
+  $customization_module                = undef,
   # DEPRECATED PARAMETERS
   $custom_theme_path                   = undef,
   $fqdn                                = undef,
diff --git a/releasenotes/notes/add-customization-module-config-option-798d0bb4e00737c3.yaml b/releasenotes/notes/add-customization-module-config-option-798d0bb4e00737c3.yaml
new file mode 100644
index 00000000..7494ad66
--- /dev/null
+++ b/releasenotes/notes/add-customization-module-config-option-798d0bb4e00737c3.yaml
@@ -0,0 +1,8 @@
+---
+features:
+  - Horizon has a global override mechanism available to perform
+    customizations. This change adds customization_module key
+    to HORIZON_CONFIG dictionary in local_settings.py. The
+    value of the parameter should be a string with the path
+    to the module containing modifications in dotted python
+    path notation.
diff --git a/spec/classes/horizon_init_spec.rb b/spec/classes/horizon_init_spec.rb
index e5d117b2..c01f661b 100644
--- a/spec/classes/horizon_init_spec.rb
+++ b/spec/classes/horizon_init_spec.rb
@@ -537,6 +537,69 @@ describe 'horizon' do
                                         ])
       end
     end
+
+    context 'with customization_module provided' do
+      before do
+        params.merge!({
+          :help_url                => 'https://docs.openstack.org',
+          :customization_module    => 'my_project.overrides',
+          :local_settings_template => fixtures_path + '/override_local_settings.py.erb'
+        })
+      end
+
+      it 'uses the custom local_settings.py template' do
+        verify_concat_fragment_contents(catalogue, 'local_settings.py', [
+          '# Custom local_settings.py',
+          "HORIZON_CONFIG = {",
+          "    'dashboards': ('project', 'admin', 'settings',),",
+          "    'default_dashboard': 'project',",
+          "    'user_home': 'openstack_dashboard.views.get_user_home',",
+          "    'ajax_queue_limit': 10,",
+          "    'auto_fade_alerts': {",
+          "        'delay': 3000,",
+          "        'fade_duration': 1500,",
+          "        'types': ['alert-success', 'alert-info']",
+          "    },",
+          "    'help_url': \"https://docs.openstack.org\",",
+          "    'exceptions': {'recoverable': exceptions.RECOVERABLE,",
+          "                   'not_found': exceptions.NOT_FOUND,",
+          "                   'unauthorized': exceptions.UNAUTHORIZED},",
+          "    'customization_module': 'my_project.overrides',",
+          "}",
+        ])
+      end
+    end
+
+    context 'with customization_module empty' do
+      before do
+        params.merge!({
+          :help_url                => 'https://docs.openstack.org',
+          :customization_module    => '',
+          :local_settings_template => fixtures_path + '/override_local_settings.py.erb'
+        })
+      end
+
+      it 'uses the custom local_settings.py template' do
+        verify_concat_fragment_contents(catalogue, 'local_settings.py', [
+          '# Custom local_settings.py',
+          "HORIZON_CONFIG = {",
+          "    'dashboards': ('project', 'admin', 'settings',),",
+          "    'default_dashboard': 'project',",
+          "    'user_home': 'openstack_dashboard.views.get_user_home',",
+          "    'ajax_queue_limit': 10,",
+          "    'auto_fade_alerts': {",
+          "        'delay': 3000,",
+          "        'fade_duration': 1500,",
+          "        'types': ['alert-success', 'alert-info']",
+          "    },",
+          "    'help_url': \"https://docs.openstack.org\",",
+          "    'exceptions': {'recoverable': exceptions.RECOVERABLE,",
+          "                   'not_found': exceptions.NOT_FOUND,",
+          "                   'unauthorized': exceptions.UNAUTHORIZED},",
+          "}",
+        ])
+      end
+    end
   end
 
   shared_examples_for 'horizon on RedHat' do
diff --git a/spec/fixtures/override_local_settings.py.erb b/spec/fixtures/override_local_settings.py.erb
index 42639652..1fb85c53 100644
--- a/spec/fixtures/override_local_settings.py.erb
+++ b/spec/fixtures/override_local_settings.py.erb
@@ -15,4 +15,7 @@ HORIZON_CONFIG = {
     'exceptions': {'recoverable': exceptions.RECOVERABLE,
                    'not_found': exceptions.NOT_FOUND,
                    'unauthorized': exceptions.UNAUTHORIZED},
+<% if @customization_module and ! (@customization_module.empty?) -%>
+    'customization_module': '<%= @customization_module -%>',
+<% end -%>
 }
diff --git a/templates/local_settings.py.erb b/templates/local_settings.py.erb
index c025c16f..5f30a1bb 100644
--- a/templates/local_settings.py.erb
+++ b/templates/local_settings.py.erb
@@ -111,6 +111,9 @@ HORIZON_CONFIG = {
     'exceptions': {'recoverable': exceptions.RECOVERABLE,
                    'not_found': exceptions.NOT_FOUND,
                    'unauthorized': exceptions.UNAUTHORIZED},
+<% if @customization_module and ! (@customization_module.empty?) -%>
+    'customization_module': '<%= @customization_module -%>',
+<% end -%>
 }
 
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