A bicycle derailleur comprises a mounting member adapted to be mounted to a bicycle frame, a base member pivotably mounted relative to the mounting member, a biasing mechanism that biases the base member clockwise relative to the mounting member when viewed laterally outwardly from the base member, a chain guide and a coupling mechanism coupled between the base member and the chain guide so that the chain guide moves relative to the base member. A rotation restricting mechanism is disposed in a force communicating path between the mounting member and the base member to restrict counterclockwise rotation of the base member relative to the mounting member.