People have a fundamental need to understand, predict, and control their environment. Causal attributions are extremely important for this. Without knowing the causes for a behavior or event, it becomes unpredictable whether it will occur again and how it might be influenced. This chapter will first introduce the topic by presenting Weiner’s attribution theory of motivation, emotion, and behavior before describing the process of causal attribution. For this purpose, the chapter will explain when and how intensively people search for causes and how they attribute them to events. Both normative and descriptive models of causal attribution will be discussed. The third part of the chapter will then talk about the effects of causal attribution on motivation, emotion, and behavior. Concretely, the chapter will describe their influence on learning and performance, the development of depressive symptoms, and aggressive behavior.