Stereotypes about aging and the old, both negative and positive, have significant influence upon older people themselves. Often unknowingly, older people incorporate these stereotypes into their own thinking and self-perceptions. A literature search revealed four primary hypotheses about the manner in which these self-stereotypes impact older people: stereotype threat, comparison, externalization, and internalization. Anecdotal examples of the four hypotheses are drawn from an unrelated research study that the authors are currently undertaking. Among these hypotheses, four basic characteristics of self-stereotypes are identified: (a) stereotypes can be negative or positive; (b) stereotypes have significant power, particularly if they are self-relevant; (c) stereotypes can be operative without awareness and influence physical and cognitive outcomes; and (d) negative stereotypes can be countered by positive priming. Due to their ability to significantly influence the cognitive and functional well-being of older people, further research is essential to better understand how these self-stereotypes function.