A buggy for transporting children has a frame (3a, 3b, 5) and wheels (9) that are rotatably mounted relative to the frame to support the frame above a ground surface. A primary seat (8) is operatively supported by the frame for supporting a first child. A secondary seat (17) is operatively supported by the frame for supporting a second child. The buggy is convertible between an in use configuration for transporting children and a folded storage configuration, whether or not the secondary seat is attached. The secondary seat may be detachable. The secondary seat may be positioned at least partly behind and at least partly below the primary seat.