The invention relates to a trailer (2) for a bicycle (1), having a braking device acting on a wheel or the wheels (4) of the trailer (2); a sensor device (12) which supplies a measured variable which is a measure of an acceleration force acting on the trailer (2) via a tow bar (5); a regulator (18) which acts on the braking device of the trailer (2) and is designed to act on the braking device, depending on the measured variable determined by the sensor device (12), in such a manner that an inertial force of the trailer (2) generated in the wheeling mode or during braking of the bicycle (1) is compensated for or is at least reduced; and a decoupling device (10; 410; 510) which is designed for the partial mechanical decoupling of a movement of the bicycle trailer (2) with respect to the bicycle (1) in the longitudinal direction of the bicycle trailer (L).