ADHD and OCD share a surprisingly similar surface presentation, yet they require fundamentally different treatment approaches. With roughly 25% of youth with OCD also meeting criteria for ADHD, and comorbidity linked to earlier onset and greater symptom severity, accurate differential diagnosis is not just clinically important; it is urgent. This session moves beyond symptom checklists and into functional analysis, equipping participants with a practical "Can't Start vs. Can't Stop" framework for distinguishing the two disorders. Through interactive case vignettes, attendees will sharpen their ability to identify whether avoidance is rooted in executive dysfunction or fear, whether repetitive behavior seeks stimulation or neutralizes threat, and whether emotional dysregulation reflects an ADHD meltdown or an obsessional trigger. The session also addresses comorbid presentations, treatment sequencing, medication considerations, and why treatment strategies may fall short when applied to the wrong diagnosis. Parent psychoeducation and the risks of accommodating either condition are highlighted throughout. Designed for clinicians, educators, and informed families, attendees will leave with actionable tools to reduce misdiagnosis and guide youth toward more targeted, effective intervention.