Dishonored is a 2012 action-adventure game developed by Arkane Studios and published by Bethesda Softworks. Set in the fictional, plague-ridden industrial city of Dunwall, Dishonored follows the story of Corvo Attano, bodyguard to the Empress of the Isles. He is framed for her murder and forced to become an assassin, seeking revenge on those who conspired against him. Corvo is aided in his quest by the Loyalists—a resistance group fighting to reclaim Dunwall, and the Outsider—a powerful being who imbues Corvo with magical abilities. Several actors, including Susan Sarandon, Brad Dourif, Carrie Fisher, Michael Madsen, John Slattery, Lena Headey and Chloë Grace Moretz, provided voice work for the game.

The game is played from a first-person perspective and allows the player to undertake a series of missions in a variety of ways, with an emphasis on player choice. Missions can be completed through stealth, combat, or a combination of both. Exploring each level opens new paths and alternatives for accomplishing mission goals, and it is possible to complete all missions, eliminating all of Corvo's targets, in a non-lethal manner. The story and missions are changed in response to the player's violent actions or lack thereof. Magical abilities and equipment are designed to be combined to create new and varied effects.

During its two and a half years in production, several versions of Dishonored were developed. Before the creation of Dunwall—inspired by late nineteenth-century London and Edinburgh—the game was set to take place in medieval Japan and seventeenth-century London. During development, test players discovered methods of exploiting the available powers and abilities to achieve unexpected outcomes; instead of restricting these techniques, the designers attempted to redesign levels to accommodate them. Dishonored's music score was produced by composer Daniel Licht to represent London in the nineteenth century.

Dishonored received positive reviews, focusing on the missions' individual narratives and the freedom available in completing them. The game won several awards, including the 2012 Spike Video Game award for Best Action-Adventure Game and the 2013 BAFTA award for Best Game, and was repeatedly recognized as the best action-adventure game of 2012 and one of that year's best games. It has also been cited as one of the greatest video games ever made. Dishonored was initially released in October 2012, for PlayStation 3, Windows, and Xbox 360, and was later supplemented with additional content focusing on the assassin Daud and his quest for redemption. PlayStation 4 and Xbox One versions of the game were released in August 2015. Two narrative sequels, Dishonored 2 and Dishonored: Death of the Outsider, were released in 2016 and 2017 respectively, and the 2021 game, Deathloop, takes place within the far future of the Dishonored universe.

Dishonored is an action-adventure game played from a first-person perspective with an emphasis on stealth action and the use of gadgets and the environment to eliminate opposing forces. The game world is a series of self-contained, mission-focused areas designed for multiple avenues of exploration in terms of in-game movement and powers. Between missions, the player is taken to a central hub called the Hound Pits pub where the player character Corvo can meet with his allies, receive mission briefings and alternate objectives, and convert recovered loot into new equipment and upgrades. In-game areas include loading docks, royal estates, poverty-stricken streets, and a bathhouse. The player can save their progress at any time (except for during combat), and the game includes a checkpoint save system. The game has four difficulty levels which modify the effectiveness of health and mana (magic) potions, and enemies' awareness, damage delivered, and responsiveness. In the easy setting, health regeneration is possible.

Dishonored features role-playing elements, such as the ability to upgrade powers and to make moral choices with a focus on non-linear consequences. The game is designed to allow the player to complete it without killing any non-player characters (NPC), including boss characters and mission targets. An example of a non-lethal situation given by co-creative designer Harvey Smith involved the player completing a side mission for a character, and in return that character had two of Corvo's targets kidnapped and enslaved. Each mission contains multiple ways to explore and reach targets. Movement through and exploration of levels is designed to support the player character's abilities, rather than specific paths that are aimed at a particular gameplay style, such as hacking or sneaking. Specific elements of missions, such as changes to the color of a target's clothing and mask in one mission are randomized, requiring the player to explore the game area to find the target each time the mission is played.

The player's actions are not judged to be good or evil, but instead are tracked by a "chaos" system that records the amounts of friendly fire, violence, and deaths the player causes. This modifies the game world, affecting the story without directly punishing the player or forcing them to choose one style of play over another. For example, an NPC who disapproves of violence may refuse to support the player, or may even betray them. The game reacts to the chaos caused in scripted ways, such as changing dialogue, and dynamic ways, such as increasing the presence of rats and plagued citizens and adding new scenes. This can affect the active mission and future missions. The system also influences which of the game's two endings is reached, with variations based on which characters live or die. Using violence allows missions to be completed in less time than using a stealth approach, but violence consumes more in-game resources such as health and mana potions, which are required more often in direct combat.

Dishonored features six active powers, four passive powers or enhancements, and 40 bone charms which grant the player supernatural perks, such as the ability to increase the duration of rat possession. Initially, only three bone charms can be active at any time; up to six can be active through optional upgrades. Smith and designer Raphaël Colantonio stated that it is impossible for a player to accrue all of the powers and abilities in a single playthrough. The player requires mana to use these abilities; mana partially regenerates after use to allow "Blink" and "Dark Vision" powers to be used, but mana potions are required to regenerate more mana, restricting the use of higher cost abilities like "Possession" and "Bend Time." Magic and ranged weapons are assigned to the player character's left hand control and a sword is assigned to the right hand control.