diff --git a/wp-admin/includes/theme.php b/wp-admin/includes/theme.php
index 36bfbe7e0c..3c0c51c98e 100644
--- a/wp-admin/includes/theme.php
+++ b/wp-admin/includes/theme.php
@@ -424,14 +424,15 @@ function wp_prepare_themes_for_js( $themes = null ) {
 
 	WP_Theme::sort_by_name( $themes );
 	foreach ( $themes as $theme ) {
+		$slug = $theme->get_stylesheet();
+		$encoded_slug = urlencode( $slug );
+
 		$parent = false;
 		if ( $theme->parent() ) {
 			$parent = $theme->parent()->display( 'Name' );
+			$parents[ $slug ] = $theme->parent()->get_stylesheet();
 		}
 
-		$slug = $theme->get_stylesheet();
-		$encoded_slug = urlencode( $slug );
-
 		$prepared_themes[ $slug ] = array(
 			'id'           => $slug,
 			'name'         => $theme->display( 'Name' ),
@@ -460,6 +461,11 @@ function wp_prepare_themes_for_js( $themes = null ) {
 		);
 	}
 
+	// Remove 'delete' action if theme has an active child
+	if ( isset( $parents ) && array_key_exists( $current_theme, $parents ) ) {
+		unset( $prepared_themes[ $parents[ $current_theme ] ]['actions']['delete'] );
+	}
+
 	/**
 	 * Filter the themes prepared for JavaScript, for themes.php.
 	 *
diff --git a/wp-admin/themes.php b/wp-admin/themes.php
index 0729f18ed4..3fa903124d 100644
--- a/wp-admin/themes.php
+++ b/wp-admin/themes.php
@@ -26,8 +26,13 @@ if ( current_user_can( 'switch_themes' ) && isset($_GET['action'] ) ) {
 		$theme = wp_get_theme( $_GET['stylesheet'] );
 		if ( !current_user_can('delete_themes') || ! $theme->exists() )
 			wp_die( __( 'Cheatin’ uh?' ), 403 );
-		delete_theme($_GET['stylesheet']);
-		wp_redirect( admin_url('themes.php?deleted=true') );
+		$active = wp_get_theme();
+		if ( $active->get( 'Template' ) == $_GET['stylesheet'] ) {
+			wp_redirect( admin_url( 'themes.php?delete-active-child=true' ) );
+		} else {
+			delete_theme( $_GET['stylesheet'] );
+			wp_redirect( admin_url( 'themes.php?deleted=true' ) );
+		}
 		exit;
 	}
 }
@@ -133,6 +138,8 @@ if ( ! validate_current_theme() || isset( $_GET['broken'] ) ) : ?>
 		}
 	elseif ( isset($_GET['deleted']) ) : ?>
 <div id="message3" class="updated"><p><?php _e('Theme deleted.') ?></p></div>
+<?php elseif ( isset( $_GET['delete-active-child'] ) ) : ?>
+	<div id="message4" class="error"><p><?php _e( 'You cannot delete a theme while it has an active child theme.' ); ?></p></div>
 <?php
 endif;
 
diff --git a/wp-includes/version.php b/wp-includes/version.php
index f92f013480..d288f4b861 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.1-beta2-30696';
+$wp_version = '4.1-beta2-30697';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.