To explore the hypothesis that domain-specific identity development predicts reasoning biases, adolescents and young adults completed measures of domain-general and domain-specific identity, epistemic regulation, and intellectual ability and evaluated arguments that either supported or threatened their occupational goals. Biases were defined as the use of sophisticated reasoning to reject goal-threatening arguments and the use of cursory reasoning to accept goal-supportive arguments. Across two measures of bias, hierarchical regression analyses showed that domain-specific vocational identity and epistemic regulation best predicted reasoning biases. Neither age nor intellectual ability predicted significant variance in biases after vocational identity and epistemic regulation scores were entered into the regression equations. The results support the thesis that biases in specific domains can be explained both by domain-specific personality attributes and by domain-general metacognitive dispositions to monitor reasoning and decontextualize problem structure from superficial contents. A dual-process framework is proposed to explain the relationships among identity, epistemic regulation, age, intellectual ability, and reasoning biases.