A walking simulator, shortened walking sim, is an adventure game that consists primarily of movement and environmental interaction. Walking sims sometimes include puzzle elements, and generally do not have combat mechanics or traditional win/lose scenarios. While these video game elements originated in the 1980s, the term began to be used pejoratively to refer to new games as walking simulators in the late 2000s, notably with Dear Esther. The term was eventually used less pejoratively and adopted by gamers, while still being negatively perceived by some game developers and retaining negative gameplay connotation. Other descriptors have been commonly used for games of such style, including empathy, narrative, and exploration game. Such games are often a hallmark of art games, but some mainstream games have been described as having walking simulator elements.

The central elements of walking simulators are controversial due to purported lack of challenge, and discontent of such games became common in the mid-to-late 2010s among "hardcore" gamers. However, the artistic aspects and emphasis on decision-making and morality are appreciated and remain popular across other video games.

Walking sims are centered around exploration, with the player being thrown into an unfamiliar environment that ranges from mundane to fantastical. The player uncovers aspects of that environment, gaining an understanding of who inhabits it and whether or not it is hostile. Most walking sims lack aspects such as combat, strategy, or economic systems. Most are also created by indie developers, although major titles such as Death Stranding have been referred to as walking sims.

Walking sims sometimes include horror game elements, adding tension to the exploration aspect. Though most survival horror games include combat and other actions the player can use to survive, some games–like Outlast and Paratopic–remove combat abilities, which leaves the player without any means to otherwise react to events. These games can be seen as walking simulators as they help to create an emotional response in their narrative by removing player agency to react to frightening events, combined with the ability to insert visual and audio cues designed to frighten the player. The Exit 8, a walking simulator inspired by the P.T. demo, requires players to walk down the same passage of a metro subway station repeatedly, turning around if they notice any differences in the passage from previous travels, creating a psychological horror experience for the player.

The name "walking simulator" often has negative connotations, implying that the gameplay is tedious and mundane. Critics, including Gamergate proponents and "hardcore" gamers, contend that walking sims are not "real games", asserting that games must include some sort of challenge or fail condition and that under this definition walking sims do not qualify as games.

Game developers–including Dan Pinchbeck, co-creator of Dear Esther–reject this narrow definition in favor of a more expansive and inclusive one. The initially pejorative term "walking simulator" was later embraced by fans, going so far as to be used as a description tag to help users find similar games on the Steam digital distribution service.

The term is sometimes used in an ironic manner. For example, upcoming game Baby Steps by Bennett Foddy has been described as a "literal walking simulator" because the character must directly control the character's legs.

Fans and developers continue to debate whether the gaming community should continue to use the term, or switch to something else. Those in support point out the mental and health benefits of walking as a sign that it is not inherently derogatory as a genre label. Detractors characterize the label as dismissive and condescending, relating it to other insults like "social justice warrior", although some have expressed a feeling of inevitability that it would continue to be used for the foreseeable future.