Stefan Kaplaniak "Cenek" (born April 10, 1933) was a Polish sprint canoer who competed from the late 1950s to the mid-1960s.
Competing in three Summer Olympics, he won a bronze medal in the K-2 1000 m event at Rome in 1960.
Kaplaniak also won two gold medals at the 1958 ICF Canoe Sprint World Championships in Prague, earning them in the K-1 500 m and K-2 500 m events.