The present invention refers to a brake assist system (1) for cyclist on a bicycle (100) including a braking system (101) having a braking member (105) capable of exerting a braking force (FB) on a front wheel (101) of the bicycle (100) by the effect of a force (Fc) applied by the cyclist on a lever (103). The system (1) includes a sensor (2) for measuring the angular speed (ω1) of the front wheel (101) of the bicycle (100); an actuator (3) capable of exerting an actuator force (FA), connectable to said braking system of the bicycle so that the actuator force (FA) opposes the force (Fc) applied by the cyclist on the lever (103), in order to reduce the braking force (FB); and a control module (4) configured for receiving, as an input, the signal representative of the angular speed (ω1) of the front wheel (101) and for determining from this a deceleration (η) of the front wheel (101).