Thomas Kastanaras (Greek: Θωμάς Καστανάρας; born 9 January 2003) is a German professional footballer who plays as a forward for Bundesliga club VfB Stuttgart.
Kastanaras played for the youth teams of TB Untertürkheim and FSV Waiblingen before he joined VfB Stuttgart in 2011. On 3 March 2022, he extended his contract with VfB Stuttgart until June 2025. After leading the club's under-19 side in scoring with 26 goals during the 2021–22 season, Kastanaras was promoted to Stuttgart's senior side for the 2022–23 season. Kastanaras made his Bundesliga debut for Stuttgart on 17 September 2022 against Eintracht Frankfurt.