The fourth legislative assembly of Madras state (3 March 1967 – 5 January 1971) was constituted in March 1967 after the assembly election which was held in February 1967. The assembly was the first non-Indian National Congress government of the state and, under chief-minister C.N. Annadurai, passed several key acts including the renaming of the state to Tamil Nadu and the abolition of the three-language formula in the state which had previously required Hindi to be taught in schools.