In recent times, physical education teachers have become increasingly aware of the "games-understanding approach" to teaching. As more physical education teachers implement physical education programs that include a games-understanding model, they are becoming increasingly in need of appropriate and authentic assessment strategies. If one accepts that teaching the "why" of game play ought to precede teaching the "how" of game play, then one must also recognize that students are likewise entitled to receive meaningful feedback regarding their development of game understanding. In this article, the authors describe appropriate tools for assessing students' understanding, based on the belief that games and game-like situations present authentic environments for assessment and that a game's classification system provides a theoretical and practical framework to assist in implementing such assessment. They present assessment scenarios and examples of tools to assess students' understanding of games within each of the four categories: (1) target games; (2) striking/fielding games; (3) net/wall games; and (4) invasion games. (Contains 5 tables.)