Kacper Stelmach (born 5 May 1997) is a Polish volleyball player, a member of Polish club GKS Katowice.
His father Andrzej is former Olympic volleyball player, six time Polish Champion. Also his uncle Krzysztof is former Olympic volleyball player, long-time member of Polish national team. He is studying economic analytics at University of Economics in Katowice.
His debuted in PlusLiga in 2015 as AZS CzÃÂstochowa player. He didn't have many chance to play in main squad so he decided to move to GKS Katowice.