A bicycle operating device comprises a base member, an operating member, and a piston. The base member has a longitudinal axis defined along a center axis of a free end of a bicycle handlebar in a mounting state where the base member is mounted to the free end of the bicycle handlebar. The base member includes a cylinder bore having a cylinder center axis. The cylinder bore is at least partly arranged in the bicycle handlebar in the mounting state. The operating member is pivotally coupled to the base member about a pivot axis. The cylinder center axis is inclined relative to the longitudinal axis by an inclination angle equal to or larger than 4 degrees. The piston is movably provided in the cylinder bore and operatively coupled to the operating member to move in the cylinder bore in response to a pivotal movement of the operating member.