Frank Winterstein (born 17 December 1986) is a Samoa international rugby league footballer who plays as a second-row forward for Toulouse Olympique in the Championship.

In October 2013, Winterstein signed a one-year deal with the Bradford Bulls while he was playing in the 2013 Rugby League World Cup with Samoa.

[4] Winterstein returned to rugby league in August 2016, signing with the Manly Warringah Sea Eagles effective immediately until the end of 2017.

He then signed a two-year deal with the French rugby league team Toulouse Olympique for the European 2020/21 seasons.

[18][19] On 22 Jan 2021, it was reported that he had left the club by mutual consent[20] Winterstein has represented Samoa internationally, first playing in the Federation Shield in 2005.