This chapter provides an overview of behavioral observation, including the contexts researchers use when observing, the forms in which they record behaviors for analysis (e.g., coding), the methods available to document that different observers coded behaviors similarly (i.e., interrater agreement, an element of reliability), the necessity of establishing other forms of reliability as well as validity, and methods of analyzing behavioral observation data. Observational settings exist along a continuum of researcher influence ranging from unfettered natural environments to tightly controlled experimental situations. Behavioral observation coding systems are of two types: topographical coding systems and dimensional coding systems. The chapter discusses the most common interrater agreement statistics, as well as some useful alternatives. When analyzing behavioral data, one must consider both how the behavior is measured and how often it is measured. The chapter describes recent analytic developments for observational data that will likely be of interest to many social-psychological researchers.