An in-wheel assembly includes an in-wheel actuator and a wheel. The in-wheel actuator includes a driving motor, a decelerator which is disposed in the driving motor and configured to decrease a rotational speed received from the driving motor, and an output shaft which is configured to receive the rotational speed decreased by the decelerator. The wheel is configured to accommodate the in-wheel actuator in an inner space and is driven by the rotational speed of the output shaft to rotate.