A bicycle brake caliper assembly comprises a brake caliper and a base structure. The brake caliper is configured to apply a braking force on a brake disc rotor configured to be rotatable about a rotational axis. The brake caliper has an attachment surface. The base structure has a first base surface. The base structure is configured to be coupled to the attachment surface of the brake caliper and to be attached to a bicycle frame so as to arrange the brake caliper at one of a first position and a second position which is farther from the rotational axis than the first position. The base structure is configured such that a relative angle defined between the attachment surface of the brake caliper and the first base surface of the base structure differs between the first position and the second position.