On the final day of the first division league, Al Salam made a return to the OPL with a 4-0 thrashing of Mussanah to finish second.
Mirbat defeated Al Seeb 2-1 to ensure the third place and book a berth in the OPL promotion playoffs against the 12th placed OPL team.
Mudhaibi was presented the trophy by Sheikh Salim al Wahaibi, the OFA chief, at the Sultan Qaboos Sports Complex.
Said al Habsi struck a 87th minute winner for Mudhaibi against Nizwa after the teams were locked in a 1-1 stalemate. The club had sealed its promotion in the previous round after playing a goalless draw against Salam.
Mudhaibi, the hometown club of Omani star Ali al Habsi, had four of his brothers directly involved with the success of the club.
Ahmed is the team director while Anwar is the coach and Harib the team captain and goalkeeper along with Sultan, the team's striker.
Salam's big win over Mussanah helped it draw level with Mirbat on 15 points each but earned the promotion, courtesy a better goal difference.
At Seeb Stadium, Mirbat came back from behind to defeat the hosts Seeb 2-1. Jefferson's double in the second half sealed the win for Mirbat.