Ganapathipillai Gangaser Ponnambalam (Tamil: கணபதி காங்கேசர் பொன்னம்பலம்; 8 November 1901 – 9 February 1977) was a Ceylon Tamil lawyer, politician and cabinet minister. He was the founder and leader of the All Ceylon Tamil Congress (ACTC), the first political party to represent the Ceylon Tamils.