Kelle Willem Roos (born 31 May 1992) is a Dutch professional footballer who plays as a goalkeeper for EFL Championship club Derby County.
He spent his youth with a wide variety of Dutch clubs, including: VV Toxandria, VV Trekvogels, Juliana '31, Quick 1888, PSV Eindhoven, Willem II, N.E.C., and Nuenen. He earned a contract at English Conference Premier side Nuneaton Town in November 2013, and gained a lot of attention from clubs throughout England with his performances during a run of clean sheets. He was sold on to Derby County for £30,000 in January 2014, and made his first-team debut for the club nine months later. He joined Rotherham United on loan in July 2015, but struggled with inconsistency and had his loan spell cancelled after just six weeks. He joined AFC Wimbledon on loan in February 2016, and enjoyed a much more successful spell, keeping goal as the club won promotion with a 2–0 victory in the 2016 League Two play-off final. He spent the first half of the 2016–17 season on loan at Bristol Rovers, and joined Port Vale and then Plymouth Argyle on emergency loans in the first half of the 2017–18 season. He broke into the Derby first-team in January 2019.