Affirmative action plans (AAPs) are designed to facilitate workplace success for members of the groups they target (e.g., women, ethnic minorities), yet may have the ironic effect of stigmatizing AAP targets and, in turn, decreasing their performance outcomes. Prior work has focused on the stigma of incompetence as the primary mechanism that links AAPs to performance; however, the broader social psychological literature suggests that additional mechanisms may also play a role. We use stereotyping theories to develop a more comprehensive model of the pathways through which AAPs limit targets' performance outcomes. Drawing from the stereotype content model, we propose that the negative effect of AAPs on others' evaluations of targets' performance is driven by perceptions of incompetence and low warmth. Drawing from stereotype threat theory, we propose that the negative effect of AAPs on targets' self-evaluated and objective performance is driven by perceptions of low self-competence, negative state affect, and perceived stereotyping by others. Meta-analytic path-analyses support our hypotheses. Our theory and findings demonstrate that multiple mechanisms explain the negative consequences of AAPs for targets' performance outcomes, highlight differences in reactions to AAP targets among others versus the self, and provide insight into preventing the unintended negative effects of AAPs.