A Powerfist is a weapon in the Warhammer 40,000 universe. It is essentially an oversized, armoured gauntlet that generates an energy field around it that disrupts any matter it touches. It is a favoured close combat weapon for the Imperium, as well as the forces of Chaos (particuarly the Chaos Space Marines). The Orks use a variant known as a Power Klaw, which is a large claw with three bladed fingers. The wielders of such weapons can easily rip apart armour of any kind with them.

In the table-top game, it has the effect of doubling the users strength while ignoring armour saves. It has the disadvantage of forcing the user to strike last, making them vulnerable to attack from others before they get a chance to strike.

Another variant is the Chainfist, similar to a Powerfist, but with a miniature powered chainsaw blade attached. In the game this gives the user greater armour penetration against vehicles.