Muslim League (Opposition), also rebel Muslim League, renamed as the All India Muslim League in 1980, was an Indian political party formed by the aggrieved leaders of Indian Union Muslim League in Kerala. The party was a member of the Communist Party of India Marxist-led Left front (later Left Democratic Front) in Kerala.

The party was organized by Ummer Bafaqy Thangal, son-in-law of the prominent Indian Union Muslim League leader Bafaqy Thangal (died 1973). All India Muslim League withdrew from the Left Democratic Front and merged with the Indian Union Muslim League in 1985.

The signs of a dissensions within ranks of the Kerala unit of the Indian Union Muslim League emerged with the deaths of senior League leaders M. Muhammed Ismail (1972) and Abdurrahiman Bafaqy Thangal (1973).

The main reasons of the rift were,

Six aggrieved League M. L. A.s refused the party whip in May 1975. They were expelled from the party, and subsequently the 'rebel Muslim League' was formed.

The Muslim League (Opposition) or 'rebel Muslim League' began to cooperate with the Communist Party of India Marxist-led Left Front from 1977 Kerala Assembly Elections.

The Muslim League (Opposition) contested the 1977 Kerala Legislative Assembly elections by fielding 16 candidates across Kerala. The party managed to receive a total of 390,139 votes (4.45% of the polled votes in Kerala). Three of its candidates were elected; P. P. V. Moosa from Edakkad, P. M. Aboobaker from Calicut-II and K. P. Raman from Kunnamangalam (S. C.).

Muslim League (Opposition) fielded two candidates in the 1977 general election. Both were defeated by Indian Union Muslim League candidates in straight contests; B. M. Hussain in the Manjeri Constituency (167,034 votes, 38.73%) and M. Moideen Kutty Haji (151,945 votes, 36.05%) in Ponnani Constituency. The party secured the 1979 by-election to the Kasaragod Legislative Assembly seat, with B. M. A. Rahiman as the candidate.