Caixinha was appointed in March and won 14 of his 26 games. He was dismissed after the Ibrox club’s board held an unscheduled meeting to discuss the Portuguese manager’s future.
Youth team coach Graeme Murty has been appointed on an interim basis. Murty previously held the caretaker role following the departure of Mark Warburton in February.
“The priority is to appoint a new manager as quickly as possible, but the board will take as much time as is necessary to secure the right person capable of representing Rangers and providing the brand of football supporters rightly expect,” said Rangers in a statement.
“The decision to part company with Pedro was taken after careful consideration and the search for a new manager will begin immediately
“Pedro was appointed in March this year but results have been disappointing and not commensurate with the level of investment that was made available.”
“We, the board, appreciate this is a difficult time for all Rangers supporters and we thank you for your patience and know Graeme and the players will receive your full backing in the days ahead.
“We thank Pedro and his backroom staff for their efforts and commitment and wish them well for the future.”
Rangers lost 2-0 to Motherwell in the semi-final of the League Cup at Hampden Park on Sunday before a Chris Burke goal in added time denied the Glasgow side a victory over Kilmarnock on Wednesday.
They are fourth in the Scottish top flight, five points behind Aberdeen and point adrift of third-placed Motherwell with bitter city rivals Celtic chasing a seventh straight title in Scotland.