Abstract: An assembly adaptor (6) for the assembly of a functional mounting (19) that is attachable on a cabinet body (1) with a frame (2) structure has an assembly plate (7) with an assembly face (14) on which the functional mounting (19) is attached. A first attachment face (9), in the mounted condition of the assembly adaptor (6), is held in abutment to a frame (2) of a cabinet body (1). An attachment part (8) with a second attachment face (10), in the assembled condition of the assembly adaptor (6), is held in abutment to a side wall (3) of the cabinet body (1). The attachment portion (8) is retainable relative to the assembly plate (7) with a variable distance between the two attachment faces (9, 10).