In multiplayer games, players will naturally need to interact with one another. Their relationships are not static and evolve over time, because players are people who make their own decisions and have their own perceptions of the game and other players. This means relationships are uncertain, because players can’t know who is trustworthy and who will deceive them. As such, fear of betrayal often greatly affects the course of a game. This study analyses how betrayal manifests in different games and aims at defining a conceptual model capable of describing betrayal in games and analysing it formally. Additionally, this study also presents a set of patterns, designed from the created model. The conceptual model and these patterns were also subjected to tests with participants.