Sithamalli Govindan Murugaiyan (15 July 1931 – 5 January 1979), usually called S.G. Murugaiyan (Tamil: எஸ்.ஜி.முருகையன்), was a communist politician in Tamil Nadu, India. S.G. Murugaiyan was a prominent leader of struggles of Dalits in Mannargudi taluk, and became the first Dalit in the state to be elected as revenue block chairman. In 1977 he was elected Member of Parliament. Two years later he was assassinated.