diff --git a/src/wp-includes/meta.php b/src/wp-includes/meta.php
index e1d0652214..e9f7811c31 100644
--- a/src/wp-includes/meta.php
+++ b/src/wp-includes/meta.php
@@ -1057,18 +1057,38 @@ class WP_Meta_Query {
 	public function parse_query_vars( $qv ) {
 		$meta_query = array();
 
-		// Simple query needs to be first for orderby=meta_value to work correctly.
+		/*
+		 * For orderby=meta_value to work correctly, simple query needs to be
+		 * first (so that its table join is against an unaliased meta table) and
+		 * needs to be its own clause (so it doesn't interfere with the logic of
+		 * the rest of the meta_query).
+		 */
+		$primary_meta_query = array();
 		foreach ( array( 'key', 'compare', 'type' ) as $key ) {
-			if ( !empty( $qv[ "meta_$key" ] ) )
-				$meta_query[0][ $key ] = $qv[ "meta_$key" ];
+			if ( ! empty( $qv[ "meta_$key" ] ) ) {
+				$primary_meta_query[ $key ] = $qv[ "meta_$key" ];
+			}
 		}
 
 		// WP_Query sets 'meta_value' = '' by default.
-		if ( isset( $qv[ 'meta_value' ] ) && '' !== $qv[ 'meta_value' ] && ( ! is_array( $qv[ 'meta_value' ] ) || $qv[ 'meta_value' ] ) )
-			$meta_query[0]['value'] = $qv[ 'meta_value' ];
+		if ( isset( $qv['meta_value'] ) && '' !== $qv['meta_value'] && ( ! is_array( $qv['meta_value'] ) || $qv['meta_value'] ) ) {
+			$primary_meta_query['value'] = $qv['meta_value'];
+		}
 
-		if ( !empty( $qv['meta_query'] ) && is_array( $qv['meta_query'] ) ) {
-			$meta_query = array_merge( $meta_query, $qv['meta_query'] );
+		$existing_meta_query = isset( $qv['meta_query'] ) && is_array( $qv['meta_query'] ) ? $qv['meta_query'] : array();
+
+		if ( ! empty( $primary_meta_query ) && ! empty( $existing_meta_query ) ) {
+			$meta_query = array(
+				'relation' => 'AND',
+				$primary_meta_query,
+				$existing_meta_query,
+			);
+		} else if ( ! empty( $primary_meta_query ) ) {
+			$meta_query = array(
+				$primary_meta_query,
+			);
+		} else if ( ! empty( $existing_meta_query ) ) {
+			$meta_query = $existing_meta_query;
 		}
 
 		$this->__construct( $meta_query );
diff --git a/tests/phpunit/tests/meta/query.php b/tests/phpunit/tests/meta/query.php
index ceee7cf931..47fe7a6d28 100644
--- a/tests/phpunit/tests/meta/query.php
+++ b/tests/phpunit/tests/meta/query.php
@@ -104,9 +104,12 @@ class Tests_Meta_Query extends WP_UnitTestCase {
 		$this->assertEquals( $expected0, $query->queries[0] );
 
 		$expected1 = array(
-			'key' => 'foo1',
-			'compare' => 'baz1',
-			'value' => 'bar1',
+			'relation' => 'OR',
+			array(
+				'key' => 'foo1',
+				'compare' => 'baz1',
+				'value' => 'bar1',
+			),
 		);
 		$this->assertEquals( $expected1, $query->queries[1] );
 	}
diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index adf683c81e..d5d16a4e6f 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -1187,6 +1187,90 @@ class Tests_Post_Query extends WP_UnitTestCase {
 		$this->assertEqualSets( array( $post_4, $post_3, $post_2, $post_1 ), $query->posts );
 	}
 
+	/**
+	 * @group meta
+	 * @ticket 29604
+	 */
+	public function test_meta_query_with_orderby_meta_value_relation_or() {
+		$posts = $this->factory->post->create_many( 4 );
+		update_post_meta( $posts[0], 'foo', 5 );
+		update_post_meta( $posts[1], 'foo', 6 );
+		update_post_meta( $posts[2], 'foo', 4 );
+		update_post_meta( $posts[3], 'foo', 7 );
+
+		update_post_meta( $posts[0], 'bar1', 'baz' );
+		update_post_meta( $posts[1], 'bar1', 'baz' );
+		update_post_meta( $posts[2], 'bar2', 'baz' );
+
+		$query = new WP_Query( array(
+			'orderby' => 'meta_value',
+			'order' => 'ASC',
+			'meta_key' => 'foo',
+			'meta_query' => array(
+				'relation' => 'OR',
+				array(
+					'key' => 'bar1',
+					'value' => 'baz',
+					'compare' => '=',
+				),
+				array(
+					'key' => 'bar2',
+					'value' => 'baz',
+					'compare' => '=',
+				),
+			),
+			'update_post_meta_cache' => false,
+			'update_post_term_cache' => false,
+			'fields' => 'ids',
+		) );
+
+		$this->assertEquals( array( $posts[2], $posts[0], $posts[1] ), $query->posts );
+	}
+
+	/**
+	 * @group meta
+	 * @ticket 29604
+	 */
+	public function test_meta_query_with_orderby_meta_value_relation_and() {
+		$posts = $this->factory->post->create_many( 4 );
+		update_post_meta( $posts[0], 'foo', 5 );
+		update_post_meta( $posts[1], 'foo', 6 );
+		update_post_meta( $posts[2], 'foo', 4 );
+		update_post_meta( $posts[3], 'foo', 7 );
+
+		update_post_meta( $posts[0], 'bar1', 'baz' );
+		update_post_meta( $posts[1], 'bar1', 'baz' );
+		update_post_meta( $posts[2], 'bar1', 'baz' );
+		update_post_meta( $posts[3], 'bar1', 'baz' );
+		update_post_meta( $posts[0], 'bar2', 'baz' );
+		update_post_meta( $posts[1], 'bar2', 'baz' );
+		update_post_meta( $posts[2], 'bar2', 'baz' );
+
+		$query = new WP_Query( array(
+			'orderby' => 'meta_value',
+			'order' => 'ASC',
+			'meta_key' => 'foo',
+			'meta_query' => array(
+				'relation' => 'AND',
+				array(
+					'key' => 'bar1',
+					'value' => 'baz',
+					'compare' => '=',
+				),
+				array(
+					'key' => 'bar2',
+					'value' => 'baz',
+					'compare' => '=',
+				),
+			),
+			'update_post_meta_cache' => false,
+			'update_post_term_cache' => false,
+			'fields' => 'ids',
+		) );
+
+		$this->assertEquals( array( $posts[2], $posts[0], $posts[1] ), $query->posts );
+	}
+
 	/**
 	 * @ticket 29642
 	 * @group meta