Person-centered personality approaches are an underused means of illuminating clinical heterogeneity of attention-deficit/hyperactivity disorder (ADHD). In the present study, latent profile analysis was conducted with personality traits to identify homogeneous profiles within the ADHD population. Participants were 548 children ages 6-18 years (302 with ADHD). Personality traits were measured via parent report on the California Q-Sort (A. Caspi et al., 1992). Latent profile analysis was conducted on the Big 5 factors. A 6-profile solution best fit the data. Resulting groups were characterized as "disagreeable," "introverted," "poor control," "well adjusted," "extraverted," and "perfectionistic." External validation of this model using ADHD diagnosis, subtypes, and comorbid psychopathology suggested that children with ADHD could be parsed into 4 groups: (a) an introverted group with high rates of the ADHD-inattentive type, (b) a group characterized by poor control, with high rates of ADHD-combined type (ADHD-C) and comorbid disruptive behavior disorders, (c) an extraverted group, with ADHD-C and few associated comorbid disorders, and (c) possibly, a very rare "perfectionistic" group, exhibiting obsessive traits. A person-centered personality approach may be one promising way to capture homogeneous subgroups within the ADHD population.