Nanayakkarapathirage Martin Perera, commonly known as Dr. N. M. Perera (Sinhala එන්.එම්.පෙරේරා [en em pe reaira]; 6 June 1904 – 14 August 1979), was one of the leaders of the Sri Lankan Trotskyist Lanka Sama Samaja Party (LSSP). He was the first Trotskyist to become a cabinet minister. He served two terms as Minister of Finance, another two as Leader of the Opposition, as well as one term as the Mayor of Colombo.

Born to Nanayakkarapathirage Abraham Perera, a rent collector at 36 St Joseph's Street, in Grandpass, Colombo, and Johana Perera. He was the fifth of nine siblings, including five boys and four girls.

Perera started his schooling in the vernacular section of St. Joseph's School, Grandpass and was later admitted to the English section. From there he spent a year at the Cathedral Boys' School, Mutwal a branch school of S. Thomas' College, Mutwal, then known as Cathedral Boys School, Mutwal. In 1919, he entered S. Thomas' College, Mount Lavinia and left in 1922 to join Ananda College. At Ananda he played cricket for the college team.

From 1922 to 1927, he studied at the University College, Colombo where he was a contemporary of J. R. Jayewardene, future president of Sri Lanka. Perera graduated with a BSc degree from the University of London External System. Thereafter he left for the United Kingdom, to enter the London School of Economics in 1927. He was in London from 1927 to 1933, where he studied under Professor Harold Laski, gaining his PhD with the thesis on the Constitution of the German Weimar Republic. This was followed by a further comparative study, of the Constitutions of the UK, United States, France and Germany; which gained him a DSc from the University of London. Perera was the first Ceylonese to gain a degree of Doctor of Science from the University of London.

Perera returned to Ceylon in 1933. The work done by Perera (as a member of the Suriya-Mal Movement) in the Kegalle district during the malaria epidemic of 1934 and during the subsequent floods gained for him the support of the poor and caste-oppressed people of the area, who called him Parippu Mahathmaya after the dhal (or parippu) he distributed as relief supplies. In 1935 Perera was one of the founder members of the LSSP and played a leading role in the party's Trotskyist activities between 1936 and 1940.

In 1936 he contested the Ruwanwella constituency, which at the time was the Thun Korale areas of Yatiyantota, Ruwanwella and Dereniyagala and parts of the present Galigamuwa electoral division, from the LSSP. His opponent was the incumbent Molamure Kumarihamy of the Meedeniya Walauwa, the feudal manor which had tremendous power over the poor people of the Sabaragamuwa area at the time. He was to hold this seat, or its Yatiyantota portion on division, continuously until 1977. Following his election, he and Philip Gunawardena, the other LSSP member of the State Council, used it as a platform voice the party's policy and objectives for complete independence from Britten, where as the Ceylon National Congress was advocating self-rule. In 1937, he formed the Ratmalana Railway Workers' Union and was the LSSP delegate to the Indian National Congress session.

With the outbreak of World War II, the Board of Ministers declared its support to the British government. The LSSP opposed the move, claiming that it was an imperialist war and organized protest. In 1939, Perera formed the All-Ceylon Estate Workers' Union and lead a militant strike at Mooloya Plantation in January 1940. Perera and Gunawardana voted against the war budget in the State Council, On protests of the planters, the Governor of Ceylon declared LSSP activity against war effort as subversive and order the police to arrest the leaders of the LSSP. On 18 June 1940, N.M. Perera, Philip Gunawardena, and Colvin R de Silva were arrested by the police with Edmund Samarakkody being arrested the following day, but Leslie Goonewardene evaded arrest. The LSSP called for a gathering to protest the arrest and carried out a protest march which was dispersed by the police with a baton charge and followed by arrests. LSSP leaders were detained at the Welikada Prison but was later transferred to the Bogambara Prison after it was suspected that they were planning a hunger strike. On 5 April 1942 during the Easter Sunday Raid, Perera along with several other imprisoned LSSP members escaped from prison. He was smuggled into Bombay in July 1942 and worked with the Bolshevik-Leninist Party of India, Ceylon and Burma (BLPI) in that country's independence struggle. He was arrested in Bombay in July 1943 and was deported to Ceylon where he was sentenced to six months' rigorous imprisonment by the Magistrates Court of Kandy for prison escape and was imprisoned in Badulla for the duration of the war. He was released in 1945.

During the war the LSSP had several divisions. With the first taking place in 1940, with the split of the ro-Moscow fraction led by S. A. Wickremasinghe, M. G. Mendis, Pieter Keuneman and A. Vaidialingam. This was followed by a second slit over N. M. Perera and Philip Gunawardena opposition to merger into the Bolshevik-Leninist Party of India, Ceylon and Burma, resulting in the formation the Workers' Opposition. After the war this faction, reconstructed the LSSP as an independent political party with N. M. Perera becoming its leader.