An electric bicycle having an electric motor mounted to a frame of the bicycle and which includes a motor output shaft defining an output end engaging a drive chain of the bicycles drive train to transmit the drive of the electric motor thereto. A torque sensor includes a base mounted in fixed relation to the frame and/or the electric motor. The torque sensor has a flexible arm extending from the base and a sensing member mounted to an extremity of the flexible arm that is displaceable relative to the base. The sensing member engages the drive chain along a segment thereof and is displaceable thereby. The segment of the drive chain extends from the output end of the motor output shaft to the pedal crank of the drive train.