Objective: Parental psychopathology and parenting quality robustly predict negative outcomes among children with ADHD. Little research has investigated associations between paternal ADHD symptoms and parenting, though there is clear evidence linking maternal ADHD symptoms with both suboptimal parenting and child conduct problems, and considerable research supporting fathers’ significant contributions to their children’s development. Method: This cross-sectional study examined psychopathology and parenting in a sample of fathers (N = 102) and their 5- to 12-year-old children with previously diagnosed ADHD. Results: Results suggested that paternal antisocial personality disorder (ASPD) symptoms (rather than ADHD symptoms) were robustly associated with child conduct problems, with an indirect effect through paternal negative parenting. Conclusion: This study suggests that negative parenting may be a potential mechanism by which paternal ASPD is associated with child conduct problems, and demonstrates the importance of considering co-occurring psychopathology in research examining adult ADHD, parenting, and child outcomes.