Creative generation is structured around existing knowledge and task examples, yet overreliance on specific examples may limit imagination (Ward, T. B., Finke, R. A., & Smith, S. M., 1995). The constraining influence of knowledge during creative generation may be offset by conceptual expansion, a process of thinking outside traditional conceptual boundaries, which may be heightened by distractibility and mild executive dysfunction (Abraham, A., Windmann, S., Daum, I., & Güntürkün, O., 2005). The present study explored the constraining effects of knowledge in adults with Attention Deficit Hyperactivity Disorder (ADHD), a disorder characterized by impaired attention and inhibitory control (Barkley, R. A., 1997). College students with and without ADHD were compared on two creative generation measures: an alien fruit invention task that required participants to imagine fruit that might exist on another planet (Ward, T.B., 1994), and a product label invention task wherein the goal was to invent product names without using elements of task examples (Kray, L.J., Galinski, A.D. & Wong, E.M., 2006). ADHD participants created alien fruit that diverged more from Earth fruit and labels that conformed less to examples, relative to non-ADHD peers. Results suggest that adults with ADHD may be less constrained by knowledge during creative generation. Findings are discussed in terms of theoretical import and practical implications for individuals with ADHD.