The attention schema theory is a proposed explanation for the brain basis of conscious experience. The theory is mechanistic, testable, and supported by at least some preliminary experiments. In the theory, subjective awareness is an internal model of attention that serves several adaptive functions. This chapter discusses the evolution of consciousness in the context of the attention schema theory, beginning with the evolution of attentional mechanisms that emerged more than half a billion years ago and extending to human consciousness and the social attribution of conscious states to others.