Lucas Clayton Sikma (born July 30, 1989) is an American professional basketball player who last played for Olympiacos of the Greek Basket League (GBL) and the Euroleague.

He was a late bloomer, growing 7 inches over two years and only making the varsity team as a junior and senior.

In 2017, Sikma won the Liga ACB with Valencia after beating Real Madrid 3–1 in the league finals.

On July 5, 2017, Sikma signed with German club Alba Berlin of the Basketball Bundesliga (BBL).

[7] On July 13, 2023, Sikma signed a two-year (1+1) deal with Olympiacos of the Greek Basket League and the EuroLeague.