A bicycle front derailleur motor unit assembly is provided that includes a motorized front derailleur mounting member and a motor unit. The front derailleur mounting member is configured to be mounted to a bicycle frame. The front derailleur mounting member includes a front derailleur mounting portion configured to be coupled to a linkage of a front derailleur and a motor unit mounting portion. The motor unit includes a motor unit housing configured to be removably coupled to the motor unit mounting portion and an output shaft configured to rotate about a rotation axis relative to the motor unit housing in first and second opposite rotational directions. The motor unit mounting portion and the motor unit housing include first and second fastener-less mating structures configured to resist rotational movement of the motor unit housing relative to the front derailleur mounting member due to a torque produced by the output shaft.