diff --git src/wp-admin/js/theme.js src/wp-admin/js/theme.js
index 1a91279..8c6bb31 100644
--- src/wp-admin/js/theme.js
+++ src/wp-admin/js/theme.js
@@ -716,7 +716,15 @@ themes.view.Details = wp.Backbone.View.extend({
 
 	// Confirmation dialog for deleting a theme
 	deleteTheme: function() {
-		return confirm( themes.data.settings.confirmDelete );
+		event.preventDefault();
+
+		$( '#delete-theme-dialog' ).removeClass( 'hidden' );
+
+		$( '#delete-theme-dialog-cancel' ).on( 'click', function() {
+			$( '#delete-theme-dialog' ).addClass( 'hidden' );
+		});
+
+		$( '#delete-theme-dialog-confirm' ).attr( 'href', $( '.delete-theme' ).attr( 'href' ) );
 	},
 
 	nextTheme: function() {
diff --git src/wp-admin/themes.php src/wp-admin/themes.php
index bf65884..83df26c 100644
--- src/wp-admin/themes.php
+++ src/wp-admin/themes.php
@@ -129,10 +129,9 @@ wp_reset_vars( array( 'theme', 'search' ) );
 wp_localize_script( 'theme', '_wpThemeSettings', array(
 	'themes'   => $themes,
 	'settings' => array(
-		'canInstall'    => ( ! is_multisite() && current_user_can( 'install_themes' ) ),
-		'installURI'    => ( ! is_multisite() && current_user_can( 'install_themes' ) ) ? admin_url( 'theme-install.php' ) : null,
-		'confirmDelete' => __( "Are you sure you want to delete this theme?\n\nClick 'Cancel' to go back, 'OK' to confirm the delete." ),
-		'adminUrl'      => parse_url( admin_url(), PHP_URL_PATH ),
+		'canInstall' => ( ! is_multisite() && current_user_can( 'install_themes' ) ),
+		'installURI' => ( ! is_multisite() && current_user_can( 'install_themes' ) ) ? admin_url( 'theme-install.php' ) : null,
+		'adminUrl'   => parse_url( admin_url(), PHP_URL_PATH ),
 	),
  	'l10n' => array(
  		'addNew'            => __( 'Add New Theme' ),
@@ -461,5 +460,17 @@ $can_install = current_user_can( 'install_themes' );
 		</div>
 	</div>
 </script>
-
+<div id="delete-theme-dialog" class="notification-dialog-wrap hidden">
+	<div class="notification-dialog-background"></div>
+	<div class="notification-dialog" style="padding:25px;">
+		<div id="delete-theme-dialog-message">
+			<p><?php _e( 'Are you sure you want to delete this theme?' ); ?></p>
+			<p><?php _e( "Click 'Cancel' to go back, 'OK' to confirm the delete." ); ?></p>
+			<p>
+				<a id="delete-theme-dialog-cancel" class="button button-secondary">Cancel</a>
+				<a id="delete-theme-dialog-confirm" class="button button-primary">Ok</a>
+			</p>
+		</div>
+	</div>
+</div>
 <?php require( ABSPATH . 'wp-admin/admin-footer.php' );