In video games, a boss is a significant computer-controlled opponent. A fight with a boss character is commonly referred to as a boss battle or boss fight. Bosses are generally far stronger than other opponents the player has faced up to that point. Boss battles are generally seen at climax points of particular sections of games, such as at the end of a level or stage or guarding a specific objective. A miniboss is a boss weaker or less significant than the main boss in the same area or level, though usually more powerful than the standard opponents and often fought alongside them. A superboss (sometimes 'secret' or 'hidden' boss) is generally much more powerful than the bosses encountered as part of the main game's plot and is often an optional encounter. A final boss is often the main antagonist of a game's story and the defeat of that character usually provides a positive conclusion to the game. A boss rush is a stage where the player faces multiple previous bosses again in succession.

For example, in a run 'n' gun video game, all regular enemies might use pistols while the boss uses a tank. A boss enemy is quite often larger in size than other enemies and the player character. At times, bosses are very hard, even impossible, to defeat without being adequately prepared and/or knowing the correct fighting approach. Bosses usually take strategy and special knowledge to defeat, such as how to attack weak points or avoid specific attacks.

Bosses are common in many genres of video games, but they are especially common in story-driven titles, and are commonly previously established antagonists in the plot of the video game. Action-adventures, beat 'em ups, fighting games, platform games, role-playing video games (RPGs), and shooter games are particularly associated with boss battles. They may be less common in puzzle games, card video games, sports games, and simulation games. The first video game with a boss fight was the 1975 RPG dnd.

The concept has expanded to new genres, like rhythm games, where there may be a "boss song" that is more difficult. In MOBA games, defeating a map boss usually requires help from the other players, but it brings various benefits to the team, such as buffs or lane push power. Some games, such as Cuphead, Furi and Warning Forever, are centered around continual boss fights.