During the past 20 years, the Implicit Association Test (IAT) has become one of the commonest measures used by researchers. In this chapter, we discuss how the IAT operates, its reliability, and its validity. We also identify important considerations for using the IAT (e.g., it is sensitive to context, it is influenced by respondent motivations, it is affected by controlled processes), revealing that it is not a pure measure of cognitive associations. Next, we examine different versions of the IAT and their implications. Finally, we explore how IAT data can be analyzed at group, individual, and aggregate levels to answer different types of empirical question. Throughout the chapter, we highlight IAT research from social psychology (where the measure originated) and consumer behavior literatures that illustrate the value of the IAT for marketing scholars and practitioners. We conclude that the IAT can be an effective tool for understanding consumer behavior, provided that researchers appreciate its weaknesses as well as its strengths in order to design sound studies and to appropriately interpret its data.