A Prussik is a friction hitch used in climbing, canyoneering, caving, rope rescue and by arborists to grab a rope (sometimes referred to as a rope-grab). The term Prusik is used both for the knot, for the loops of cord, and for the action (to prusik). More casually, the term is used for any friction hitch that can grab a rope.

The Prussik hitch is named for its inventor, Austrian mountaineer Dr. Karl Prusik. It was shown in a 1931 Austrian mountaineering manual for rope ascending. It was used on several mountaineering routes of the era to ascend the final summit block of a peak; where a rope could be thrown over the top, one side anchored, and climbers could attain the summit by prussiking up the other side of the rope.