A wing (1) having a fixed wing (3) and a wing tip device (4) rotatable between a flight configuration and a ground configuration, a rotational joint (10) rotatably couples the wing tip device (4) to the fixed wing (3) and a locking mechanism (46) locks the wing tip device (4) in the flight and ground configurations. The locking mechanism (11) includes first and second locking members (51, 52) and first and second receiving members (53, 54), the locking mechanism (11) being configured to lock the wing tip device (4) in one of the flight configuration and ground configuration by receiving the first and second locking members (51, 52) in the first and second receiving members (53, 54) respectively, and to lock the wing tip device (4) in the other of the flight configuration and ground configuration by receiving the first locking member (51) in the second receiving member (54).