This course extends the analysis of Microeconomics I to situations with strategic interactions, that is, of economic situations where the choice of an agent has an impact on the utility of other agents. This involves, for example, the analysis of public goods, and different mechanisms to allocate goods such as auctions or bargaining. We will first provide choice under uncertainty, the basic elements of (non-cooperative) game theory, the main tool to analyze strategic interactions in economics. This will include the basic notions of equilibrium and refinements (Nash, subgame perfection, Bayesian equilibrium, Perfect Bayesian Equilibrium…). As we proceed, we will apply this toolbox to the study of several economic questions including firms’ decisions in oligopoly markets, individual provision to a public good, bidding behavior in several auction formats, and the analysis of repeated interactions. If there is time, we are going to introduce some basic ideas of cooperative game theory.