A board to board connector assembly (1) includes a first connector (2) suitable to be arranged on a first printed circuit board (3) and a second connector (4) suitable to be arranged on a second printed circuit board (5). An adapter (6) is arranged in a mounted position between and interconnected to the first and the second connector (2, 4). The adapter (6) includes an adapter inner conductor (7) and an adapter outer conductor (8). The adapter outer conductor (8) is arranged separate from the adapter inner conductor (7) and comprises a bore (18) in which the adapter inner conductor (7) is arranged.