A kneeskin is a type of competitive swimwear worn by both male and female athletes. Kneeskins are normally made of technologically advanced lycra-based fabrics designed to hug the body tightly and provide increased speed and decreased drag resistance in the water.

The kneeskin is similar in design to the full bodyskin absent the leggings beyond the knee. It also resembles a "shortie" style wetsuit only made of drag-reducing fabric instead of neoprene and commonly features a zippered back. Most competitive swimwear brands such as the Speedo Fastskin line and Tyr produce suits of this type. As with most technologically advanced fabric swimwear, kneeskin suits are only commonly used at highly competitive levels of the swimming sport and are known to sell for prices in excess of $200 American.