Theodoros "Thodoris" Vlachos (Greek: Θοδωρής Βλάχος, born 9 July 1969 in Volos) is a retired Greek water polo player and the current coach of Olympiacos Water Polo Club and the Greece men's national water polo team. In 2014, he became head coach of Greece national team, whom he led to the bronze medal at the 2015 World Aquatics Championships in Kazan and the bronze medal at the 2016 World League in Huizhou.