diff --git a/src/js/_enqueues/wp/theme.js b/src/js/_enqueues/wp/theme.js
index cfcea1fcc58b7..98dc490635ed2 100644
--- a/src/js/_enqueues/wp/theme.js
+++ b/src/js/_enqueues/wp/theme.js
@@ -8,13 +8,12 @@ window.wp = window.wp || {};
 ( function($) {
 
 // Set up our namespace...
-var themes, l10n;
+var themes;
 themes = wp.themes = wp.themes || {};
 
 // Store the theme data and settings for organized and quick access.
-// themes.data.settings, themes.data.themes, themes.data.l10n.
+// themes.data.settings, themes.data.themes.
 themes.data = _wpThemeSettings;
-l10n = themes.data.l10n;
 
 /**
  * Announces to screen readers the theme shown after previous/next navigation.
@@ -143,7 +142,7 @@ themes.view.Appearance = wp.Backbone.View.extend({
 		view.render();
 		this.searchContainer
 			.find( '.search-box' )
-			.append( $.parseHTML( '<label for="wp-filter-search-input">' + l10n.search + '</label>' ) )
+			.append( $.parseHTML( '<label for="wp-filter-search-input">' + ( themes.isInstall ? wp.i18n.__( 'Search Themes' ) : wp.i18n.__( 'Search installed themes' ) ) + '</label>' ) )
 			.append( view.el );
 
 		this.searchContainer.on( 'submit', function( event ) {
@@ -1005,9 +1004,9 @@ themes.view.Preview = themes.view.Details.extend({
 	collapse: function( event ) {
 		var $button = $( event.currentTarget );
 		if ( 'true' === $button.attr( 'aria-expanded' ) ) {
-			$button.attr({ 'aria-expanded': 'false', 'aria-label': l10n.expandSidebar });
+			$button.attr({ 'aria-expanded': 'false', 'aria-label': wp.i18n.__( 'Expand Sidebar' ) });
 		} else {
-			$button.attr({ 'aria-expanded': 'true', 'aria-label': l10n.collapseSidebar });
+			$button.attr({ 'aria-expanded': 'true', 'aria-label': wp.i18n.__( 'Collapse Sidebar' ) });
 		}
 
 		this.$el.toggleClass( 'collapsed' ).toggleClass( 'expanded' );
@@ -1257,7 +1256,7 @@ themes.view.Themes = wp.Backbone.View.extend({
 
 		// 'Add new theme' element shown at the end of the grid.
 		if ( ! themes.isInstall && themes.data.settings.canInstall ) {
-			this.$el.append( '<div class="theme add-new-theme"><a href="' + themes.data.settings.installURI + '"><div class="theme-screenshot"><span aria-hidden="true"></span></div><h2 class="theme-name">' + l10n.addNew + '</h2></a></div>' );
+			this.$el.append( '<div class="theme add-new-theme"><a href="' + themes.data.settings.installURI + '"><div class="theme-screenshot"><span aria-hidden="true"></span></div><h2 class="theme-name">' + wp.i18n.__( 'Add Theme' ) + '</h2></a></div>' );
 		}
 
 		this.parent.page++;
@@ -1313,7 +1312,7 @@ themes.view.Themes = wp.Backbone.View.extend({
 				$modal.find( '.notice-warning' )
 					.removeClass( 'notice-large' )
 					.addClass( 'updating-message' )
-					.find( 'p' ).text( wp.updates.l10n.updating );
+					.find( 'p' ).text( wp.i18n.__( 'Updating...' ) );
 			} else if ( $card.find( '.notice-error' ).length ) {
 				$modal.find( '.notice-warning' ).remove();
 			}
@@ -1400,9 +1399,10 @@ themes.view.Themes = wp.Backbone.View.extend({
 	// Dispatch audible search results feedback message.
 	announceSearchResults: function( count ) {
 		if ( 0 === count ) {
-			wp.a11y.speak( l10n.noThemesFound );
+			wp.a11y.speak( wp.i18n.__( 'No themes found. Try a different search.' ) );
 		} else {
-			wp.a11y.speak( l10n.themesFound.replace( '%d', count ) );
+			/* translators: %d: Number of themes. */
+			wp.a11y.speak( wp.i18n.sprintf( wp.i18n.__( 'Number of Themes found: %d' ), count ) );
 		}
 	}
 });
@@ -1720,7 +1720,8 @@ themes.view.Installer = themes.view.Appearance.extend({
 		this.listenTo( this.collection, 'query:fail', function() {
 			$( 'body' ).removeClass( 'loading-content' );
 			$( '.theme-browser' ).find( 'div.error' ).remove();
-			$( '.theme-browser' ).find( 'div.themes' ).before( '<div class="notice notice-error"><p>' + l10n.error + '</p><p><button class="button try-again">' + l10n.tryAgain + '</button></p></div>' );
+			/* translators: %s: Support forums URL. */
+			$( '.theme-browser' ).find( 'div.themes' ).before( '<div class="notice notice-error"><p>' + wp.i18n.sprintf( wp.i18n.__( 'An unexpected error occurred. Something may be wrong with WordPress.org or this server&#8217;s configuration. If you continue to have problems, please try the <a href="%s">support forums</a>.' ), 'https://wordpress.org/support/forums/' ) + '</p><p><button class="button try-again">' + wp.i18n.__( 'Try Again' ) + '</button></p></div>' );
 			$( '.theme-browser .error .try-again' ).on( 'click', function( e ) {
 				e.preventDefault();
 				$( 'input.wp-filter-search' ).trigger( 'input' );
@@ -1852,7 +1853,8 @@ themes.view.Installer = themes.view.Appearance.extend({
 		}
 
 		if ( ! tags ) {
-			wp.a11y.speak( l10n.selectFeatureFilter );
+			/* translators: Hidden accessibility text. */
+			wp.a11y.speak( wp.i18n.__( 'Select one or more Theme features to filter by' ) );
 			return;
 		}
 
diff --git a/src/wp-admin/theme-install.php b/src/wp-admin/theme-install.php
index 8e6fc5d1eea2c..8a9c86367c4d3 100644
--- a/src/wp-admin/theme-install.php
+++ b/src/wp-admin/theme-install.php
@@ -80,6 +80,7 @@
 );
 
 wp_enqueue_script( 'theme' );
+wp_set_script_translations( 'theme' );
 wp_enqueue_script( 'updates' );
 
 if ( $tab ) {
diff --git a/src/wp-admin/themes.php b/src/wp-admin/themes.php
index ac2cd4a9824cb..ab84510d03a52 100644
--- a/src/wp-admin/themes.php
+++ b/src/wp-admin/themes.php
@@ -245,6 +245,7 @@
 
 add_thickbox();
 wp_enqueue_script( 'theme' );
+wp_set_script_translations( 'theme' );
 wp_enqueue_script( 'updates' );
 
 require_once ABSPATH . 'wp-admin/admin-header.php';