Gameification (or, gamification) is becoming an increasingly popular technique to motivate learners, yet little theory or empirical evidence is available to support its use. In the present chapter, instructional design in relation to games and gameification is explored, including discussion of the psychological determinants of learning. The extant research literatures surrounding online social media, learning-by-testing, and goal-setting theory are then integrated in order to provide a scientific rationale for gameification. The resulting integrative theory of gameification in learning suggests that students may learn more by completing tests than they do when studying, that students can be motivated to complete such tests by offering them social rewards in the form of carefully designed virtual badges, and that these badges should be offered in an online social context which students find meaningful in order to motivate them to action. To examine this integrative theory, an online social network with gameification elements was created and deployed in a Psychology department at a major east coast university in order to motivate students to complete optional online multiple choice quizzes. The system was highly successful; 29% of participants opted to complete gameified optional multiple choice quizzes and on average reported those quizzes as fun, enjoyable, and rewarding. This proof-of-concept study is discussed in terms of its implications for both undergraduate education and employee training, including a list of current “best practices” regarding social game implementation.