This chapter discusses the endocrine and neural control of the social behaviors in lizards. Many of the physiological mechanisms involved in controlling reptilian sexual and aggressive behaviors are very similar to those in other vertebrate groups; however, some intriguing differences exist. Steroid hormones are important in the control of reproductive behavior in both sexes in many different vertebrate species. Much of the work done in whiptail lizards has examined the role of gonadal sex in controlling social behaviors. The Amygdala is important in the control of male reproductive behavior in mammals, birds, fish, amphibians, and reptiles. While membrane receptors exist, steroid hormones commonly function through genomic actions via intracellular receptors. In lizards, aggressive displays by conspecifics can activate brain areas involved in visual processing, such as the anterior dorsal ventricular ridge, basal ganglia, and nucleus rotundus in Anolis carolinensis males.