diff --git a/mu-plugins/10up-plugin/plugin.php b/mu-plugins/10up-plugin/plugin.php
index ccc77f74..f7cc9628 100755
--- a/mu-plugins/10up-plugin/plugin.php
+++ b/mu-plugins/10up-plugin/plugin.php
@@ -16,6 +16,8 @@
  * @package           TenUpPlugin
  */
 
+declare( strict_types = 1 );
+
 // Useful global constants.
 define( 'TENUP_PLUGIN_VERSION', '0.1.0' );
 define( 'TENUP_PLUGIN_URL', plugin_dir_url( __FILE__ ) );
diff --git a/mu-plugins/10up-plugin/src/Assets.php b/mu-plugins/10up-plugin/src/Assets.php
index c9a6607c..7deb5967 100644
--- a/mu-plugins/10up-plugin/src/Assets.php
+++ b/mu-plugins/10up-plugin/src/Assets.php
@@ -5,6 +5,8 @@
  * @package TenUpPlugin
  */
 
+declare( strict_types = 1 );
+
 namespace TenUpPlugin;
 
 use TenupFramework\Assets\GetAssetInfo;
@@ -26,7 +28,7 @@ class Assets implements ModuleInterface {
 	 *
 	 * @return bool
 	 */
-	public function can_register() {
+	public function can_register(): bool {
 		return true;
 	}
 
@@ -35,7 +37,7 @@ public function can_register() {
 	 *
 	 * @return void
 	 */
-	public function register() {
+	public function register(): void {
 		$this->setup_asset_vars(
 			dist_path: TENUP_PLUGIN_PATH . 'dist/',
 			fallback_version: TENUP_PLUGIN_VERSION
@@ -50,7 +52,7 @@ public function register() {
 	 *
 	 * @return void
 	 */
-	public function admin_scripts() {
+	public function admin_scripts(): void {
 		wp_enqueue_script(
 			'tenup_plugin_admin',
 			TENUP_PLUGIN_URL . 'dist/js/admin.js',
@@ -65,7 +67,7 @@ public function admin_scripts() {
 	 *
 	 * @return void
 	 */
-	public function admin_styles() {
+	public function admin_styles(): void {
 		wp_enqueue_style(
 			'tenup_plugin_admin',
 			TENUP_PLUGIN_URL . 'dist/css/admin.css',
diff --git a/mu-plugins/10up-plugin/src/Core/Emoji.php b/mu-plugins/10up-plugin/src/Core/Emoji.php
index b3d58357..4a4885f4 100644
--- a/mu-plugins/10up-plugin/src/Core/Emoji.php
+++ b/mu-plugins/10up-plugin/src/Core/Emoji.php
@@ -5,6 +5,8 @@
  * @package TenUpPlugin/Core
  */
 
+declare( strict_types = 1 );
+
 namespace TenUpPlugin\Core;
 
 use TenupFramework\Module;
diff --git a/mu-plugins/10up-plugin/src/Core/HeadOverrides.php b/mu-plugins/10up-plugin/src/Core/HeadOverrides.php
index f2b926ef..94063d3e 100644
--- a/mu-plugins/10up-plugin/src/Core/HeadOverrides.php
+++ b/mu-plugins/10up-plugin/src/Core/HeadOverrides.php
@@ -5,6 +5,8 @@
  * @package TenUpPlugin/Core
  */
 
+declare( strict_types = 1 );
+
 namespace TenUpPlugin\Core;
 
 use TenupFramework\Module;
diff --git a/mu-plugins/10up-plugin/src/PluginCore.php b/mu-plugins/10up-plugin/src/PluginCore.php
index f30e9f69..b92f2554 100644
--- a/mu-plugins/10up-plugin/src/PluginCore.php
+++ b/mu-plugins/10up-plugin/src/PluginCore.php
@@ -5,6 +5,8 @@
  * @package TenUpPlugin
  */
 
+declare( strict_types = 1 );
+
 namespace TenUpPlugin;
 
 use TenupFramework\ModuleInitialization;
diff --git a/mu-plugins/10up-plugin/src/PostTypes/Demo.php b/mu-plugins/10up-plugin/src/PostTypes/Demo.php
index c22f2ad5..a4cd1ecf 100644
--- a/mu-plugins/10up-plugin/src/PostTypes/Demo.php
+++ b/mu-plugins/10up-plugin/src/PostTypes/Demo.php
@@ -5,6 +5,8 @@
  * @package TenUpPlugin
  */
 
+declare( strict_types = 1 );
+
 namespace TenUpPlugin\PostTypes;
 
 use TenupFramework\PostTypes\AbstractPostType;
@@ -19,7 +21,7 @@ class Demo extends AbstractPostType {
 	 *
 	 * @return string
 	 */
-	public function get_name() {
+	public function get_name(): string {
 		return 'tenup-demo';
 	}
 
@@ -28,7 +30,7 @@ public function get_name() {
 	 *
 	 * @return string
 	 */
-	public function get_singular_label() {
+	public function get_singular_label(): string {
 		return esc_html__( 'Demo', 'tenup-plugin' );
 	}
 
@@ -37,7 +39,7 @@ public function get_singular_label() {
 	 *
 	 * @return string
 	 */
-	public function get_plural_label() {
+	public function get_plural_label(): string {
 		return esc_html__( 'Demos', 'tenup-plugin' );
 	}
 
@@ -50,7 +52,7 @@ public function get_plural_label() {
 	 *
 	 * @return string
 	 */
-	public function get_menu_icon() {
+	public function get_menu_icon(): string {
 		return 'dashicons-chart-pie';
 	}
 
@@ -59,7 +61,7 @@ public function get_menu_icon() {
 	 *
 	 * @return bool
 	 */
-	public function can_register() {
+	public function can_register(): bool {
 		return false;
 	}
 
@@ -69,7 +71,7 @@ public function can_register() {
 	 *
 	 * @return array<string>
 	 */
-	public function get_supported_taxonomies() {
+	public function get_supported_taxonomies(): array {
 		return [
 			'tenup-tax-demo',
 		];
@@ -80,7 +82,7 @@ public function get_supported_taxonomies() {
 	 *
 	 * @return void
 	 */
-	public function after_register() {
+	public function after_register(): void {
 		// Register any hooks/filters you need.
 	}
 }
diff --git a/mu-plugins/10up-plugin/src/PostTypes/Page.php b/mu-plugins/10up-plugin/src/PostTypes/Page.php
index 98bdeb8c..0fe48df4 100644
--- a/mu-plugins/10up-plugin/src/PostTypes/Page.php
+++ b/mu-plugins/10up-plugin/src/PostTypes/Page.php
@@ -5,6 +5,8 @@
  * @package TenUpPlugin
  */
 
+declare( strict_types = 1 );
+
 namespace TenUpPlugin\PostTypes;
 
 use TenupFramework\PostTypes\AbstractCorePostType;
@@ -22,7 +24,7 @@ class Page extends AbstractCorePostType {
 	 *
 	 * @return string
 	 */
-	public function get_name() {
+	public function get_name(): string {
 		return 'page';
 	}
 
@@ -32,7 +34,7 @@ public function get_name() {
 	 *
 	 * @return array<string>
 	 */
-	public function get_supported_taxonomies() {
+	public function get_supported_taxonomies(): array {
 		return [];
 	}
 
@@ -41,7 +43,7 @@ public function get_supported_taxonomies() {
 	 *
 	 * @return void
 	 */
-	public function after_register() {
+	public function after_register(): void {
 		// Do nothing.
 	}
 }
diff --git a/mu-plugins/10up-plugin/src/PostTypes/Post.php b/mu-plugins/10up-plugin/src/PostTypes/Post.php
index a84fe7d8..0a919e5e 100644
--- a/mu-plugins/10up-plugin/src/PostTypes/Post.php
+++ b/mu-plugins/10up-plugin/src/PostTypes/Post.php
@@ -5,6 +5,8 @@
  * @package TenUpPlugin
  */
 
+declare( strict_types = 1 );
+
 namespace TenUpPlugin\PostTypes;
 
 use TenupFramework\PostTypes\AbstractCorePostType;
@@ -22,7 +24,7 @@ class Post extends AbstractCorePostType {
 	 *
 	 * @return string
 	 */
-	public function get_name() {
+	public function get_name(): string {
 		return 'post';
 	}
 
@@ -34,7 +36,7 @@ public function get_name() {
 	 *
 	 * @return array<string>
 	 */
-	public function get_supported_taxonomies() {
+	public function get_supported_taxonomies(): array {
 		return [];
 	}
 
@@ -43,7 +45,7 @@ public function get_supported_taxonomies() {
 	 *
 	 * @return void
 	 */
-	public function after_register() {
+	public function after_register(): void {
 		// Do nothing.
 	}
 }
diff --git a/mu-plugins/10up-plugin/src/Taxonomies/Demo.php b/mu-plugins/10up-plugin/src/Taxonomies/Demo.php
index ad89ce24..098281dc 100644
--- a/mu-plugins/10up-plugin/src/Taxonomies/Demo.php
+++ b/mu-plugins/10up-plugin/src/Taxonomies/Demo.php
@@ -5,6 +5,8 @@
  * @package TenUpPlugin
  */
 
+declare( strict_types = 1 );
+
 namespace TenUpPlugin\Taxonomies;
 
 use TenupFramework\Taxonomies\AbstractTaxonomy;
@@ -19,7 +21,7 @@ class Demo extends AbstractTaxonomy {
 	 *
 	 * @return string
 	 */
-	public function get_name() {
+	public function get_name(): string {
 		return 'tenup-tax-demo';
 	}
 
@@ -28,7 +30,7 @@ public function get_name() {
 	 *
 	 * @return string
 	 */
-	public function get_singular_label() {
+	public function get_singular_label(): string {
 		return esc_html__( 'Demo Term', 'tenup-plugin' );
 	}
 
@@ -37,7 +39,7 @@ public function get_singular_label() {
 	 *
 	 * @return string
 	 */
-	public function get_plural_label() {
+	public function get_plural_label(): string {
 		return esc_html__( 'Demo Terms', 'tenup-plugin' );
 	}
 
@@ -46,7 +48,7 @@ public function get_plural_label() {
 	 *
 	 * @return bool
 	 */
-	public function can_register() {
+	public function can_register(): bool {
 		return false;
 	}
 }
diff --git a/themes/10up-block-theme/src/Assets.php b/themes/10up-block-theme/src/Assets.php
index d2bc60e7..d8ee273b 100644
--- a/themes/10up-block-theme/src/Assets.php
+++ b/themes/10up-block-theme/src/Assets.php
@@ -5,6 +5,8 @@
  * @package TenupBlockTheme
  */
 
+declare( strict_types = 1 );
+
 namespace TenupBlockTheme;
 
 use TenupFramework\Assets\GetAssetInfo;
@@ -26,7 +28,7 @@ class Assets implements ModuleInterface {
 	 *
 	 * @return bool
 	 */
-	public function can_register() {
+	public function can_register(): bool {
 		return true;
 	}
 
@@ -35,7 +37,7 @@ public function can_register() {
 	 *
 	 * @return void
 	 */
-	public function register() {
+	public function register(): void {
 		$this->setup_asset_vars(
 			dist_path: TENUP_BLOCK_THEME_DIST_PATH,
 			fallback_version: TENUP_BLOCK_THEME_VERSION
@@ -51,7 +53,7 @@ public function register() {
 	 *
 	 * @return void
 	 */
-	public function enqueue_frontend_assets() {
+	public function enqueue_frontend_assets(): void {
 		wp_enqueue_style(
 			'tenup-theme-styles',
 			TENUP_BLOCK_THEME_TEMPLATE_URL . '/dist/css/frontend.css',
@@ -77,7 +79,7 @@ public function enqueue_frontend_assets() {
 	 *
 	 * @return void
 	 */
-	public function enqueue_block_editor_assets() {
+	public function enqueue_block_editor_assets(): void {
 		wp_enqueue_style(
 			'tenup-theme-editor-frame-style-overrides',
 			TENUP_BLOCK_THEME_TEMPLATE_URL . '/dist/css/editor-frame-style-overrides.css',
@@ -99,7 +101,7 @@ public function enqueue_block_editor_assets() {
 	 *
 	 * @return void
 	 */
-	public function enqueue_block_editor_iframe_assets() {
+	public function enqueue_block_editor_iframe_assets(): void {
 
 		// The `enqueue_block_assets` action is triggered both on the front-end and in the editor iframe.
 		// We only want to enqueue these styles inside the editor iframe.
@@ -120,7 +122,7 @@ public function enqueue_block_editor_iframe_assets() {
 	 *
 	 * @return void
 	 */
-	public function register_all_icons() {
+	public function register_all_icons(): void {
 		if ( ! function_exists( '\UIKitCore\Helpers\register_icons' ) ) {
 			return;
 		}
diff --git a/themes/10up-block-theme/src/Blocks.php b/themes/10up-block-theme/src/Blocks.php
index f689eec3..186dde0f 100644
--- a/themes/10up-block-theme/src/Blocks.php
+++ b/themes/10up-block-theme/src/Blocks.php
@@ -5,6 +5,8 @@
  * @package TenupBlockTheme
  */
 
+declare( strict_types = 1 );
+
 namespace TenupBlockTheme;
 
 use TenupFramework\Assets\GetAssetInfo;
@@ -26,7 +28,7 @@ class Blocks implements ModuleInterface {
 	 *
 	 * @return bool
 	 */
-	public function can_register() {
+	public function can_register(): bool {
 		return true;
 	}
 
@@ -35,7 +37,7 @@ public function can_register() {
 	 *
 	 * @return void
 	 */
-	public function register() {
+	public function register(): void {
 		$this->setup_asset_vars(
 			dist_path: TENUP_BLOCK_THEME_DIST_PATH,
 			fallback_version: TENUP_BLOCK_THEME_VERSION
@@ -53,7 +55,7 @@ public function register() {
 	 *
 	 * @return void
 	 */
-	public function register_theme_blocks() {
+	public function register_theme_blocks(): void {
 		// Register all the blocks in the theme.
 		if ( file_exists( TENUP_BLOCK_THEME_BLOCK_DIST_DIR ) ) {
 			$block_json_files = glob( TENUP_BLOCK_THEME_BLOCK_DIST_DIR . '*/block.json' );
@@ -91,7 +93,7 @@ function ( array|bool $allowed_blocks ) use ( $block_names ): array|bool {
 	 *
 	 * @return void
 	 */
-	public function enqueue_theme_block_styles() {
+	public function enqueue_theme_block_styles(): void {
 		$stylesheets = glob( TENUP_BLOCK_THEME_DIST_PATH . '/blocks/autoenqueue/**/*.css' );
 
 		if ( empty( $stylesheets ) ) {
diff --git a/themes/10up-block-theme/src/TemplateTags.php b/themes/10up-block-theme/src/TemplateTags.php
index 95e77e5f..59661e04 100644
--- a/themes/10up-block-theme/src/TemplateTags.php
+++ b/themes/10up-block-theme/src/TemplateTags.php
@@ -5,6 +5,8 @@
  * @package TenupBlockTheme
  */
 
+declare( strict_types = 1 );
+
 namespace TenupBlockTheme;
 
 use TenupFramework\Module;
@@ -24,7 +26,7 @@ class TemplateTags implements ModuleInterface {
 	 *
 	 * @return bool
 	 */
-	public function can_register() {
+	public function can_register(): bool {
 		return true;
 	}
 
@@ -33,7 +35,7 @@ public function can_register() {
 	 *
 	 * @return void
 	 */
-	public function register() {
+	public function register(): void {
 		add_action( 'wp_head', [ $this, 'add_viewport_meta_tag' ], 10, 0 );
 	}
 
@@ -42,7 +44,7 @@ public function register() {
 	 *
 	 * @return void
 	 */
-	public function add_viewport_meta_tag() {
+	public function add_viewport_meta_tag(): void {
 		?>
 		<meta name="viewport" content="width=device-width, initial-scale=1.0, viewport-fit=cover">
 		<?php
diff --git a/themes/10up-block-theme/src/ThemeCore.php b/themes/10up-block-theme/src/ThemeCore.php
index 20deae07..424b6754 100644
--- a/themes/10up-block-theme/src/ThemeCore.php
+++ b/themes/10up-block-theme/src/ThemeCore.php
@@ -5,6 +5,8 @@
  * @package TenupBlockTheme
  */
 
+declare( strict_types = 1 );
+
 namespace TenupBlockTheme;
 
 use TenupFramework\ModuleInitialization;
diff --git a/themes/10up-theme/src/Assets.php b/themes/10up-theme/src/Assets.php
index c660632b..d6a0c997 100644
--- a/themes/10up-theme/src/Assets.php
+++ b/themes/10up-theme/src/Assets.php
@@ -5,6 +5,8 @@
  * @package TenUpTheme
  */
 
+declare( strict_types = 1 );
+
 namespace TenUpTheme;
 
 use TenupFramework\Assets\GetAssetInfo;
@@ -26,7 +28,7 @@ class Assets implements ModuleInterface {
 	 *
 	 * @return bool
 	 */
-	public function can_register() {
+	public function can_register(): bool {
 		return true;
 	}
 
@@ -35,7 +37,7 @@ public function can_register() {
 	 *
 	 * @return void
 	 */
-	public function register() {
+	public function register(): void {
 		$this->setup_asset_vars(
 			dist_path: TENUP_THEME_DIST_PATH,
 			fallback_version: TENUP_THEME_VERSION
@@ -51,7 +53,7 @@ public function register() {
 	 *
 	 * @return void
 	 */
-	public function scripts() {
+	public function scripts(): void {
 		/**
 		 * Enqueuing frontend.js is required to get css hot reloading working in the frontend
 		 * If you're not shipping any front-end js wrap this enqueue in a SCRIPT_DEBUG check.
@@ -70,7 +72,7 @@ public function scripts() {
 	 *
 	 * @return void
 	 */
-	public function enqueue_block_editor_scripts() {
+	public function enqueue_block_editor_scripts(): void {
 		wp_enqueue_script(
 			'block-editor-script',
 			TENUP_THEME_DIST_URL . 'js/block-editor-script.js',
@@ -85,7 +87,7 @@ public function enqueue_block_editor_scripts() {
 	 *
 	 * @return void
 	 */
-	public function styles() {
+	public function styles(): void {
 		wp_enqueue_style(
 			'styles',
 			TENUP_THEME_TEMPLATE_URL . '/dist/css/frontend.css',
diff --git a/themes/10up-theme/src/Blocks.php b/themes/10up-theme/src/Blocks.php
index 306bdd7a..e734551b 100644
--- a/themes/10up-theme/src/Blocks.php
+++ b/themes/10up-theme/src/Blocks.php
@@ -5,6 +5,8 @@
  * @package TenUpTheme
  */
 
+declare( strict_types = 1 );
+
 namespace TenUpTheme;
 
 use TenupFramework\Assets\GetAssetInfo;
@@ -26,7 +28,7 @@ class Blocks implements ModuleInterface {
 	 *
 	 * @return bool
 	 */
-	public function can_register() {
+	public function can_register(): bool {
 		return true;
 	}
 
@@ -35,7 +37,7 @@ public function can_register() {
 	 *
 	 * @return void
 	 */
-	public function register() {
+	public function register(): void {
 		$this->setup_asset_vars(
 			dist_path: TENUP_THEME_DIST_PATH,
 			fallback_version: TENUP_THEME_VERSION
@@ -55,7 +57,7 @@ public function register() {
 	 *
 	 * @return void
 	 */
-	public function register_theme_blocks() {
+	public function register_theme_blocks(): void {
 		// Register all the blocks in the theme
 		if ( file_exists( TENUP_THEME_BLOCK_DIST_DIR ) ) {
 			$block_json_files = glob( TENUP_THEME_BLOCK_DIST_DIR . '*/block.json' );
@@ -97,7 +99,7 @@ public function register_theme_blocks() {
 	 *
 	 * @return void
 	 */
-	public function blocks_editor_styles() {
+	public function blocks_editor_styles(): void {
 		wp_enqueue_style(
 			'editor-style-overrides',
 			TENUP_THEME_TEMPLATE_URL . '/dist/css/editor-style-overrides.css',
@@ -132,7 +134,7 @@ public function blocks_editor_styles() {
 	 *
 	 * @return void
 	 */
-	public function enqueue_block_specific_styles() {
+	public function enqueue_block_specific_styles(): void {
 		$stylesheets = glob( TENUP_THEME_DIST_PATH . 'blocks/autoenqueue/**/*.css' );
 
 		if ( empty( $stylesheets ) ) {
@@ -179,7 +181,7 @@ public function enqueue_block_specific_styles() {
 	 *
 	 * @return void
 	 */
-	public function register_block_pattern_categories() {
+	public function register_block_pattern_categories(): void {
 		// Register a block pattern category
 		register_block_pattern_category(
 			'10up-theme',
diff --git a/themes/10up-theme/src/ThemeCore.php b/themes/10up-theme/src/ThemeCore.php
index b42b8d2d..1958ea19 100644
--- a/themes/10up-theme/src/ThemeCore.php
+++ b/themes/10up-theme/src/ThemeCore.php
@@ -5,6 +5,8 @@
  * @package TenUpTheme
  */
 
+declare( strict_types = 1 );
+
 namespace TenUpTheme;
 
 use TenupFramework\ModuleInitialization;