Politics is a complex affair. Whether one is a legislator or a citizen, making political decisions is rarely easy. The question of how people deal with this complexity has been on the minds of scholars for decades, if not centuries. One important answer, which emerged in the 1970s, is that decision makers rely on heuristics to tame the intricacies of politics. Heuristics are (cognitive) shortcuts that allow decision makers to bypass a great deal of information while producing an output in the form of a judgment or choice. Often such outputs are indistinguishable from what a complete consideration of the decision-relevant information would have produced. At other times the outputs may not be optimal, but they are good enough. It can also happen, however, that heuristics introduce formidable biases and result in inferior decisions. This chapter reviews the literature on heuristics use by the mass public and political elites. It discusses the kinds of heuristics that are used, how they function, and why they are both inevitable and fallible. Finally, the chapter considers the normative implications of heuristics in political behavior.