Drawing on social comparison and identity literature, we suggest that individuals' comparisons of themselves to their own standards of leadership relate to their leadership motivation. We propose and test a model of motivation to lead (MTL) based on two types of self-to-leader comparisons: self-to-exemplar and self-to-prototype comparisons with respect to affiliation. In our main study, using data from a sample of 180 executives, we apply structural equation models to test our predictions. We find that self-comparisons with concrete, influential leaders of the past or present (self-to-exemplar comparisons) relate positively to MTL. We also find that self-comparisons with more general representations of leaders (self-to-prototype comparisons in affiliation) relate to MTL. Whereas the effect of self-to-exemplar comparisons is mediated through individuals' leadership self-efficacy perceptions, the effect of self-to-prototype comparisons is not. We replicate these findings in three follow-up studies using different research designs. We derive implications for theory and practice.