Silas Ostrzinski (born 19 November 2003) is a German professional footballer who plays as a goalkeeper for Borussia Dortmund II.
Ostrzinski joined the youth academy of Borussia Dortmund in 2018 from SpVg Hagen 11. On 14 April 2022, he extended his contract with Dortmund and was promoted to their reserves in the 3. Liga. On 13 June 2023, he again extended his contract with the club until 2025. He made the senior Borussa Dortmund squad for the 2025 FIFA Club World Cup.
Born in Germany, Ostrzinski is of Polish descent. In March 2024, he was on-call for the Germany U20s.