Kaspar Treier (born 19 September 1999) is an Estonian professional basketball player for Napoli Basket of the Italian Lega Basket Serie A (LBA).

On 4 August 2017, Treier signed with Poderosa Montegranaro of the Serie A2.

On 10 June 2019, Treier signed with Felice Scandone of the Lega Basket Serie A (LBA).

Treier made his debut for the Estonian national team on 30 November 2018, in a 2019 FIBA Basketball World Cup qualifier against Georgia.

This biographical article relating to an Estonian basketball figure is a stub.