A bicycle brake caliper assembly comprises a brake caliper and a base member. The brake caliper is configured to apply a braking force on a brake disc rotor configured to be rotatable about a rotational axis. The base member is configured to be coupled to the brake caliper and to be attached to a bicycle frame such that relative position between the rotational axis of the brake disc rotor and the brake caliper is adjustable in a radial direction of the brake disc rotor. The base member includes a first coupling portion at which the brake caliper is coupled, and a second coupling portion at which the brake caliper is coupled and which is arranged apart from the first coupling portion in the radial direction.