Konstantinos Kostoulas (; born 8 February 2005) is a Greek professional footballer who plays as a centre-back for Super League club OFI.
Kostoulas started his career with Agia Anna Volos, before joining Olympiacos in 2019. He progressed through the academy to make his debut for Olympiacos B in Super League Greece 2 in March 2024. In July 2024, he joined Primeira Liga side Rio Ave on loan for the season. On 18 April 2025, he made his professional league debut for Rio Ave, playing the full match in a 1âÂÂ1 draw with Santa Clara. In July 2025, Kostoulas joined Super League Greece side OFI on a three-year deal.
Kostoulas has represented Grece at under-19 and under-21 level.
Kostoulas is the son of former Greek international footballer Athanasios Kostoulas, while his brother, Charalampos, plays for Brighton & Hove Albion.