In video games, a power-up is an object that adds temporary benefits or extra abilities to the player character as a game mechanic. This is in contrast to an item, which may or may not have a permanent benefit that can be used at any time chosen by the player. Although often collected directly through touch, power-ups can sometimes only be gained by collecting several related items, such as the floating letters of the word 'EXTEND' in Bubble Bobble. Well known examples of power-ups that have entered popular culture include the power capsules from Pac-Man (regarded as the first power-up) and the Super Mushroom from Super Mario Bros., which ranked first in UGO Networks' Top 11 Video Game Powerups.

Items that confer power-ups are usually pre-placed in the game world, spawned randomly, dropped by beaten enemies or picked up from opened or smashed containers. They can be differentiated from items in other games, such as role-playing video games, by the fact that they take effect immediately, feature designs that do not necessarily fit into the game world (often used letters or symbols emblazoned on a design), and are found in specific genres of games. Power-ups are mostly found in action-oriented games such as maze games, run and guns, shoot 'em ups, first-person shooters, and platform games.

The term "power-up" is an example of wasei-eigo (Japanese pseudo-Anglicisms); the sense was coined in Japanese as a compound of "power" (パワー, pawā; noun) and "up" (アップする, appusuru; verb), literally "to up someone's or something's power or abilities". The general meaning of X-up in Japanese is "this will increase your X", and this construction is regularly used in areas such as advertising.^{[verification needed]}

Pac-Man from 1980 is credited as the first video game to feature a power-up mechanic, though at the time they were called "power capsules" by the manufacturers. Every maze in the game contains four Power Pellets which temporarily give Pac-Man the ability to eat ghosts, turning the tables on his pursuers. The effect of the power-up was illustrated by one of the first cut scenes to appear in a video game, in the form of brief comical interludes about Pac-Man and Blinky chasing each other around. The power pellet entered popular culture with a joke on video game controversies regarding the influence of video games on children.

In 1984, Sabre Wulf introduced power-ups in the form of flowers which, when blossoming, provided effects such as speed up and invincibility.

In 1985, Super Mario Bros. introduced the Super Mushroom, which has entered popular culture, being described as "the quintessential power-up". The original game idea was to have an always big Mario as a technical advance, but later the power-up was introduced to make him "super" as a bonus effect. The development team thought it would be interesting to have Mario grow and shrink by eating a magic mushroom, just like in Alice's Adventures in Wonderland. Other power-ups introduced in this game were the Super Stars and Fire Flowers, which gave Mario invincibility and the ability to shoot fireballs at enemies, respectively.

Konami's 1985 game Gradius had the first use of a selection bar where the player could select which power-up effect to trigger, instead of having a fixed instant effect.

In 1986 and the years after, the concept of permanent power-ups appeared in the action role-playing genre in the form of perks.