Our purpose in this paper is to review studies that explored the impact of the use of mobile games in both formal and informal learning environments. Through a review of studies on mobile learning that have been published between 2000 and 2013, we aim to identify the ways in which researchers used mobile games in a variety of learning environments, and to synthesize current literature about the impact of the use of mobile games on student achievement and attitudes towards and learning. We first provide definitions of the constructs "mobile technologies," "mobile games," and "informal learning environments." Following that, we present the outcomes of our analysis by describing the purpose, the contexts, and the findings of each of the studies we reviewed. We then offer general conclusions that came out of our analysis and we offer some recommendations for future research.