Samuel Luke Johnstone (born 25 March 1993) is an English professional footballer who plays as goalkeeper for West Bromwich Albion.
A product of the Manchester United Academy, he has spent time on loan with Oldham Athletic, Scunthorpe United, Walsall, Yeovil Town, Doncaster Rovers, Preston North End and Aston Villa.
He was an England youth international, winning caps at under-16, under-17, under-19 and under-20 levels.
He is the son of Glenn Johnstone, a former professional footballer who played as a goalkeeper for Preston North End in the early 1990s.