Lassi Thomson (born 24 September 2000) is a Finnish junior ice hockey defenseman who is currently playing with the Ilves in the Liiga as a prospect to the Ottawa Senators of the National Hockey League (NHL).
He was drafted 19th overall by the Senators in the first round of the 2019 NHL Entry Draft.
Thomson's father is Scottish.On July 15, 2019, Thomson was signed to a three-year, entry-level contract with the Ottawa Senators.