diff --git a/src/wp-includes/link-template.php b/src/wp-includes/link-template.php
index 0fe8a942b8..17748ddabc 100644
--- a/src/wp-includes/link-template.php
+++ b/src/wp-includes/link-template.php
@@ -1521,6 +1521,36 @@ function get_adjacent_post( $in_same_term = false, $excluded_terms = '', $previo
 		}
 	}
 
+	// 'post_status' clause depends on the current user.
+	if ( is_user_logged_in() ) {
+		$user_id = get_current_user_id();
+
+		$post_type_object = get_post_type_object( $post->post_type );
+		if ( empty( $post_type_object ) ) {
+			$post_type_cap    = $post->post_type;
+			$read_private_cap = 'read_private_' . $post_type_cap . 's';
+		} else {
+			$read_private_cap = $post_type_object->cap->read_private_posts;
+		}
+
+		/*
+		 * Results should include private posts belonging to the current user, or private posts where the
+		 * current user has the 'read_private_posts' cap.
+		 */
+		$private_states = get_post_stati( array( 'private' => true ) );
+		$where .= " AND ( p.post_status = 'publish'";
+		foreach ( (array) $private_states as $state ) {
+			if ( current_user_can( $read_private_cap ) ) {
+				$where .= $wpdb->prepare( " OR p.post_status = %s", $state );
+			} else {
+				$where .= $wpdb->prepare( " OR (p.post_author = %d AND p.post_status = %s)", $user_id, $state );
+			}
+		}
+		$where .= " )";
+	} else {
+		$where .= " AND p.post_status = 'publish'";
+	}
+
 	$adjacent = $previous ? 'previous' : 'next';
 	$op = $previous ? '<' : '>';
 	$order = $previous ? 'DESC' : 'ASC';
@@ -1551,7 +1581,7 @@ function get_adjacent_post( $in_same_term = false, $excluded_terms = '', $previo
 	 * @param bool   $in_same_term   Whether post should be in a same taxonomy term.
 	 * @param array  $excluded_terms Array of excluded term IDs.
 	 */
-	$where = apply_filters( "get_{$adjacent}_post_where", $wpdb->prepare( "WHERE p.post_date $op %s AND p.post_type = %s AND p.post_status = 'publish' $where", $current_post_date, $post->post_type ), $in_same_term, $excluded_terms );
+	$where = apply_filters( "get_{$adjacent}_post_where", $wpdb->prepare( "WHERE p.post_date $op %s AND p.post_type = %s $where", $current_post_date, $post->post_type ), $in_same_term, $excluded_terms );
 
 	/**
 	 * Filter the ORDER BY clause in the SQL for an adjacent post query.
diff --git a/tests/phpunit/tests/url.php b/tests/phpunit/tests/url.php
index 15da8ca8bf..1bc7ba5c02 100644
--- a/tests/phpunit/tests/url.php
+++ b/tests/phpunit/tests/url.php
@@ -279,10 +279,10 @@ class Tests_URL extends WP_UnitTestCase {
 		force_ssl_login( $forced_login );
 	}
 
-	function test_get_adjacent_post() {
-		$post_id = $this->factory->post->create();
-		sleep( 1 ); // get_adjacent_post() doesn't handle posts created in the same second.
-		$post_id2 = $this->factory->post->create();
+	public function test_get_adjacent_post() {
+		$now = time();
+		$post_id = $this->factory->post->create( array( 'post_date' => date( 'Y-m-d H:i:s', $now - 1 ) ) );
+		$post_id2 = $this->factory->post->create( array( 'post_date' => date( 'Y-m-d H:i:s', $now ) ) );
 
 		if ( ! isset( $GLOBALS['post'] ) )
 			$GLOBALS['post'] = null;
@@ -306,9 +306,89 @@ class Tests_URL extends WP_UnitTestCase {
 		$this->assertNull( get_adjacent_post() );
 
 		$GLOBALS['post'] = $orig_post;
+	}
 
-		// Tests requiring creating more posts can't be run since the query
-		// cache in get_adjacent_post() requires a fresh page load to invalidate.
+	/**
+	 * Test get_adjacent_post returns the next private post when the author is the currently logged in user.
+	 *
+	 * @ticket 30287
+	 */
+	public function test_get_adjacent_post_should_return_private_posts_belonging_to_the_current_user() {
+		$u = $this->factory->user->create( array( 'role' => 'author' ) );
+		$old_uid = get_current_user_id();
+		wp_set_current_user( $u );
+
+		$now = time();
+		$p1 = $this->factory->post->create( array( 'post_author' => $u, 'post_status' => 'private', 'post_date' => date( 'Y-m-d H:i:s', $now - 1 ) ) );
+		$p2 = $this->factory->post->create( array( 'post_author' => $u, 'post_date' => date( 'Y-m-d H:i:s', $now ) ) );
+
+		if ( ! isset( $GLOBALS['post'] ) ) {
+			$GLOBALS['post'] = null;
+		}
+		$orig_post = $GLOBALS['post'];
+
+		$GLOBALS['post'] = get_post( $p2 );
+
+		$p = get_adjacent_post();
+		$this->assertEquals( $p1, $p->ID );
+
+		$GLOBALS['post'] = $orig_post;
+		wp_set_current_user( $old_uid );
+	}
+
+	/**
+	 * @ticket 30287
+	 */
+	public function test_get_adjacent_post_should_return_private_posts_belonging_to_other_users_if_the_current_user_can_read_private_posts() {
+		$u1 = $this->factory->user->create( array( 'role' => 'author' ) );
+		$u2 = $this->factory->user->create( array( 'role' => 'administrator' ) );
+		$old_uid = get_current_user_id();
+		wp_set_current_user( $u2 );
+
+		$now = time();
+		$p1 = $this->factory->post->create( array( 'post_author' => $u1, 'post_status' => 'private', 'post_date' => date( 'Y-m-d H:i:s', $now - 1 ) ) );
+		$p2 = $this->factory->post->create( array( 'post_author' => $u1, 'post_date' => date( 'Y-m-d H:i:s', $now ) ) );
+
+		if ( ! isset( $GLOBALS['post'] ) ) {
+			$GLOBALS['post'] = null;
+		}
+		$orig_post = $GLOBALS['post'];
+
+		$GLOBALS['post'] = get_post( $p2 );
+
+		$p = get_adjacent_post();
+		$this->assertEquals( $p1, $p->ID );
+
+		$GLOBALS['post'] = $orig_post;
+		wp_set_current_user( $old_uid );
+	}
+
+	/**
+	 * @ticket 30287
+	 */
+	public function test_get_adjacent_post_should_not_return_private_posts_belonging_to_other_users_if_the_current_user_cannot_read_private_posts() {
+		$u1 = $this->factory->user->create( array( 'role' => 'author' ) );
+		$u2 = $this->factory->user->create( array( 'role' => 'author' ) );
+		$old_uid = get_current_user_id();
+		wp_set_current_user( $u2 );
+
+		$now = time();
+		$p1 = $this->factory->post->create( array( 'post_author' => $u1, 'post_date' => date( 'Y-m-d H:i:s', $now - 2 ) ) );
+		$p2 = $this->factory->post->create( array( 'post_author' => $u1, 'post_status' => 'private', 'post_date' => date( 'Y-m-d H:i:s', $now - 1 ) ) );
+		$p3 = $this->factory->post->create( array( 'post_author' => $u1, 'post_date' => date( 'Y-m-d H:i:s', $now ) ) );
+
+		if ( ! isset( $GLOBALS['post'] ) ) {
+			$GLOBALS['post'] = null;
+		}
+		$orig_post = $GLOBALS['post'];
+
+		$GLOBALS['post'] = get_post( $p3 );
+
+		$p = get_adjacent_post();
+		$this->assertEquals( $p1, $p->ID );
+
+		$GLOBALS['post'] = $orig_post;
+		wp_set_current_user( $old_uid );
 	}
 
 	/**