David S. Vethamuthu (Tamil: வே. தேவிட்) (26 August 1932 – 10 July 2005) was a Malaysian unionist and former opposition politician. He won a seat in the Malaysian parliament four times, representing the constituencies of Bangsar, Dato' Kramat, Damansara and Puchong. While in parliament, he was known to be fearless and vocal in raising issues concerning the Indian community in Malaysia. He later became the chairman of the World Tamil Association in 1984. He is famously known for making Labour Day a public holiday in Malaysia.