diff --git a/src/wp-includes/class-http.php b/src/wp-includes/class-http.php
index 232ef69c3b..b2b00623d8 100644
--- a/src/wp-includes/class-http.php
+++ b/src/wp-includes/class-http.php
@@ -675,16 +675,17 @@ class WP_Http {
 		if ( empty( $url ) )
 			return $maybe_relative_path;
 
-		// Check for a scheme.
-		if ( false !== strpos( $maybe_relative_path, '://' ) )
-			return $maybe_relative_path;
-
 		if ( ! $url_parts = @parse_url( $url ) )
 			return $maybe_relative_path;
 
 		if ( ! $relative_url_parts = @parse_url( $maybe_relative_path ) )
 			return $maybe_relative_path;
 
+		// Check for a scheme on the 'relative' url
+		if ( ! empty( $relative_url_parts['scheme'] ) ) {
+			return $maybe_relative_path;
+		}
+
 		$absolute_path = $url_parts['scheme'] . '://' . $url_parts['host'];
 		if ( isset( $url_parts['port'] ) )
 			$absolute_path .= ':' . $url_parts['port'];
diff --git a/tests/phpunit/tests/http/http.php b/tests/phpunit/tests/http/http.php
index 578d6e84a8..995220794f 100644
--- a/tests/phpunit/tests/http/http.php
+++ b/tests/phpunit/tests/http/http.php
@@ -56,7 +56,11 @@ class Tests_HTTP_HTTP extends WP_UnitTestCase {
 			array( 'otherfile.ext?query=string', 'http://example.com/file.ext?existing=query-string', 'http://example.com/otherfile.ext?query=string' ),
 
 			// A file with a leading dot
-			array( '.ext', 'http://example.com/', 'http://example.com/.ext' )
+			array( '.ext', 'http://example.com/', 'http://example.com/.ext' ),
+
+			// URls within URLs
+			array( '/expected', 'http://example.com/sub/http://site.com/sub/', 'http://example.com/expected' ),
+			array( '/expected/http://site.com/sub/', 'http://example.com/', 'http://example.com/expected/http://site.com/sub/' ),
 		);
 	}
 }