The use of voice interactions in home voice assistants are becoming mainstream and it’s being used to everything from information seeking to personal management. Even though games utilising voice has been praised for its innovation it has never been anything other than a novelty and research has been scarce. This study explores how a voice user interface (VUI) can be designed to reduce in-game interruptions in an open world video game environment. Through literature research, interviews, observations and prototypes aimed towards people playing video games and users of VUIs, this thesis proposes a set of design qualities for future implementation. The findings show that designing for voice interactions in an open world video game is, among other things, a matter of providing context-based triggers together with a compressed and modular approach that does not require the user to shift their attention from the video game.