Mahendravarma I (Tamil: மகேந்திரவர்மன் 600–630 CE) was a Pallava king who ruled the Northern regions of what forms present-day Tamil Nadu in India in the early 7th century. He was the son of Simhavishnu, who defeated the Kalabhras and re-established the Pallava kingdom.
During his reign, the Chalukya king Pulakeshin II attacked the Pallava kingdom. The Pallavas fought a series of wars in the northern Vengi region, before Mahendravarma decimated his chief enemies at Pullalur (according to Pallava grants at Kuram, kasakudi and tadantottam). Although Mahendravarma saved his capital, he lost the northern provinces to Pulakeshin. Tamil literature flourished under his rule, with the rise in popularity of Tevaram written by Appar and Sambandhar. He himself was the author of the play Mattavilasa Prahasana and another play called Bhagavadajjuka.
Mahendravarma was succeeded to the throne by his more famous son Narasimhavarman I in 630 CE. At last he defeated Pulakeshin II and ransacked the Chalukyan capital city Vatapi (also known as Badami).