Lachlan Olbrich (born 30 December 2003) is an Australian professional basketball player for the Chicago Bulls of the National Basketball Association (NBA), on a two-way contract with the Windy City Bulls of the NBA G League. In 2022, he was named in the NBL1 Central All-Star Five playing for the Southern Tigers. After a season of college basketball in the United States for the UC Riverside Highlanders, he returned to the NBL1 Central in 2023 and helped the West Adelaide Bearcats win the championship while earning grand final MVP and All-Star Five honours. He joined the Illawarra Hawks for the 2023–24 NBL season and then had a championship-winning season with the Canterbury Rams in the 2024 New Zealand NBL season. With the Rams, he was named grand final MVP, league MVP and All-Star Five.

After winning an NBL championship with the Illawarra Hawks in the 2024–25 season, Olbrich was drafted by the Los Angeles Lakers in the second round of the 2025 NBA draft.