Evolutionary psychology provides a comprehensive framework for conceptualizing the cognitive and affective mechanisms that humans possess, one of which is self-esteem. Sociometer theory is arguably one of the leading theories of self-esteem from an evolutionary psychology perspective. The current chapter reviews the evidence for sociometer theory within the context of the core premises of evolutionary psychology in an attempt to understand the role and function of self-esteem. Although there is mounting support for this theory, there are still areas that require further investigation, such as the number of sociometers that exist and the domain-specific versus domain-general nature of these gauges of social inclusion.