diff --git a/src/wp-admin/includes/post.php b/src/wp-admin/includes/post.php
index 142752dbc8..ec96749f46 100644
--- a/src/wp-admin/includes/post.php
+++ b/src/wp-admin/includes/post.php
@@ -177,6 +177,7 @@ function _wp_translate_postdata( $update = false, $post_data = null ) {
  * @return int Post ID.
  */
 function edit_post( $post_data = null ) {
+	global $wpdb;
 
 	if ( empty($post_data) )
 		$post_data = &$_POST;
@@ -317,7 +318,19 @@ function edit_post( $post_data = null ) {
 
 	update_post_meta( $post_ID, '_edit_last', get_current_user_id() );
 
-	wp_update_post( $post_data );
+	$success = wp_update_post( $post_data );
+	// If the save failed, see if we can sanity check the main fields and try again
+	if ( ! $success && is_callable( array( $wpdb, 'strip_invalid_text_for_column' ) ) ) {
+		$fields = array( 'post_title', 'post_content', 'post_excerpt' );
+
+		foreach( $fields as $field ) {
+			if ( isset( $post_data[ $field ] ) ) {
+				$post_data[ $field ] = $wpdb->strip_invalid_text_for_column( $wpdb->posts, $field, $post_data[ $field ] );
+			}
+		}
+
+		wp_update_post( $post_data );
+	}
 
 	// Now that we have an ID we can fix any attachment anchor hrefs
 	_fix_attachment_links( $post_ID );
diff --git a/tests/phpunit/tests/post.php b/tests/phpunit/tests/post.php
index a4c68223bf..94f6817463 100644
--- a/tests/phpunit/tests/post.php
+++ b/tests/phpunit/tests/post.php
@@ -1016,4 +1016,41 @@ class Tests_Post extends WP_UnitTestCase {
 		_unregister_post_type( 'post-type-1' );
 		_unregister_post_type( 'post-type-2' );
 	}
+
+	/**
+	 * @ticket 21212
+	 */
+	function test_utf8mb3_post_saves_with_emoji() {
+		global $wpdb;
+		$_wpdb = new wpdb_exposed_methods_for_testing();
+
+		if ( 'utf8' !== $_wpdb->get_col_charset( $wpdb->posts, 'post_title' ) ) {
+			$this->markTestSkipped( 'This test is only useful with the utf8 character set' );
+		}
+
+		require_once( ABSPATH . '/wp-admin/includes/post.php' );
+
+		$post_id = $this->factory->post->create();
+
+		$data = array(
+			'post_ID'      => $post_id,
+			'post_title'   => "foo\xf0\x9f\x98\x88bar",
+			'post_content' => "foo\xf0\x9f\x98\x8ebaz",
+			'post_excerpt' => "foo\xf0\x9f\x98\x90bat"
+		);
+
+		$expected = array(
+			'post_title'   => "foobar",
+			'post_content' => "foobaz",
+			'post_excerpt' => "foobat"
+		);
+
+		edit_post( $data );
+
+		$post = get_post( $post_id );
+
+		foreach( $expected as $field => $value ) {
+			$this->assertEquals( $post->$field, $value );
+		}
+	}
 }