Sociability in mice is a multidimensional adaptive and functional response. Due to its complexity, it is important that researchers use well-defined behavioral assays that are easily replicated with clearly defined ethograms. In the Mouse Behavioral and Neuroendocrine Analysis Core Facility at Duke University, we have developed a broad series of tests that examine different components of neonatal and adult social behaviors that include sociability, sexual behavior, aggressive and territorial responses, and maternal behaviors. While the purpose of this chapter is not to provide an exhaustive description of all mouse social tests available, we provide investigators with a description of basic procedures and considerations necessary to develop a successful social behavior testing program within their laboratories.