Iain Armitage is an American actor. He is best known for his role as Sheldon Cooper in Young Sheldon, a spin-off prequel to The Big Bang Theory, from 2017 to 2024. He also played Ziggy Chapman in Big Little Lies (2017–2019) and voiced young Shaggy Rogers in Scoob! (2020) and Chase in PAW Patrol: The Movie (2021).