While learning games have received a large amount of attention and research in the last few years, there is still a large gap with regard to workplace learning. Very little literature is available that aims to develop a set of design principles specific to a learning setting that differs significantly from traditional classrooms. Therefore, the goal of this work is to elicit discussion on the design of game-based learning for the workplace, as well to encourage research in this crucial, but often forgotten, learning setting. In this paper I first consider these differences and examine the joint media engagement (JME) framework as it applies to the workplace. I then examine existing literature on game design and use in the workplace. Based on this literature, I propose a set of design principles for workplace-based instructional games based on the joint media engagement (JME) framework.