Many real-world decisions are strategic in the sense that the optimal course of action depends on the behavior of others. For example, this holds for firms competing with each other, bidders in auctions, parties in negotiations, employees competing for promotions, politicians in electoral competition, or players in games like poker, chess, or soccer. The present lecture provides an introduction to game theory in order to be able to analyze such interdependent decision-making. Students will learn how to formulate a strategic interaction as a game. Students will be introduced to various solution concepts, such as Nash equilibrium, subgame perfect equilibrium, and perfect Bayesian equilibrium.