According to emerging research, adult Attention-Deficit/Hyperactivity Disorder (ADHD) is an often misunderstood psychiatric diagnosis that can be easily overlooked in the clinical setting. A systematic review of the literature revealed that improper treatment may include decreased knowledge of diagnosis, fear of treating adults with stimulant medications, or disbelief that ADHD persists into adulthood. The purpose of this Evidence-Based Practice (EBP) project was to describe the level of nurse practitioner (NP) knowledge regarding adult ADHD before and after NP participation in a teaching intervention addressing adult ADHD.