A connector assembly (10, 10A) comprising a connector (20, 20A) and a mating connector (60, 60A), wherein: the mating connector (60, 60A) comprises a first mating terminal (82, 82A), a second mating terminal (84, 84A) and a mating housing (70, 70A); the mating housing holds the first mating terminal and the second mating terminal; the mating housing forms a receiving portion (62, 62A); the mating housing is formed with a release projection (722, 722A) and a mating lock portion; the release projection projects into the receiving portion (62, 62A); the mating lock portion faces the receiving portion; the connector (20, 20A) is mateable with the mating connector (60, 60A) along a mating direction; the connector (20, 20A) comprises a first terminal (52, 52A), a first housing (30,30A), a second terminal (54, 54A) and a second housing (40, 40A); the first housing (30, 30A) is configured to be received into the receiving portion (62, 62A) along the mating direction; the first housing holds the first terminal (52, 52A); the first terminal is connected to the first mating terminal (82, 82A) when the first housing is received in the receiving portion (62, 62A); the first housing is provided with a stopper (350, 366A) and a first structure (36, 36A) which includes a first support portion (362, 362A) and a lock portion; the first support portion has a restoring force and supports the lock portion; the lock portion is movable in a perpendicular direction perpendicular to the mating direction by using the restoring force of the first support portion; the lock portion and the mating lock portion lock a state where the first housing is received in the receiving portion when the first terminal is connected to the first mating terminal; the second housing holds the second terminal; the second housing is provided with a stopped portion (464, 464A) and a regulation portion (442, 461A); one of the first housing and the second housing is provided with a second support portion (46, 462A); the second support portion has a restoring force and supports a supported portion which is one of the stopper and the stopped portion; the supported portion is movable in the perpendicular direction by using the restoring force of the second support portion; when the second housing is installed to the first housing along the mating direction, the stopped portion is brought into abutment with the stopper, and the second housing takes a regulated state where a movement of the second housing in the mating direction is regulated by the stopper; when the second housing under the regulated state is received into the receiving portion along the mating direction together with the first housing, the first terminal is connected to the first mating terminal, and then one of the second support portion and the supported portion is brought into abutment with the release projection so that a movement regulation of the second housing in the mating direction is released; and when the second housing is further moved in the mating direction after release of the movement regulation, the second terminal is connected to the second mating terminal, and the regulation portion is located inward of at least a part of the first structure in the perpendicular direction to regulate a movement of the lock portion in the perpendicular direction. the first support portion has a restoring force and supports the lock portion; the lock portion is movable in a perpendicular direction perpendicular to the mating direction by using the restoring force of the first support portion; the lock portion and the mating lock portion lock a state where the first housing is received in the receiving portion when the first terminal is connected to the first mating terminal; the second housing holds the second terminal; the second housing is provided with a stopped portion (464, 464A) and a regulation portion (442, 461A); one of the first housing and the second housing is provided with a second support portion (46, 462A); the second support portion has a restoring force and supports a supported portion which is one of the stopper and the stopped portion; the supported portion is movable in the perpendicular direction by using the restoring force of the second support portion; when the second housing is installed to the first housing along the mating direction, the stopped portion is brought into abutment with the stopper, and the second housing takes a regulated state where a movement of the second housing in the mating direction is regulated by the stopper; when the second housing under the regulated state is received into the receiving portion along the mating direction together with the first housing, the first terminal is connected to the first mating terminal, and then one of the second support portion and the supported portion is brought into abutment with the release projection so that a movement regulation of the second housing in the mating direction is released; and when the second housing is further moved in the mating direction after release of the movement regulation, the second terminal is connected to the second mating terminal, and the regulation portion is located inward of at least a part of the first structure in the perpendicular direction to regulate a movement of the lock portion in the perpendicular direction.