Ozhalur Viswanatha Mudaliar Alagesan (Tamil: ஒழலூர் விஸ்வநாத முதலியார் அழககேசன்) (6 September 1911 – 3 January 1992) was an Indian politician and freedom fighter from the Indian state of Tamil Nadu. He served as a Member of parliament, Lok Sabha from 1951 to 1957, 1962 to 1967 and from 1971 to 1979.
Alagesan was a member of the Constituent Assembly from 1946 to 1951. In 1951, he was elected Member of Parliament from Chingleput. He lost the elections in 1957 but was re-elected in 1962. He also served as a Member of Parliament from Tiruthani from 1971 to 1975 and Arakkonam from 1975 to 1979.
Alagesan served as India's Ambassador to Ethiopia from 1968 to 1971.
Alagesan died on 3 January 1992 at the age of 81.