The STEM (science, technology, engineering, and mathematics) potential of youth with cognitive disabilities is often dismissed through problematic perceptions of STEM ability as natural and of youth with cognitive disabilities as unable. National data on more than 15,000 adolescents from the High School Longitudinal Study of 2009 first suggest that, among youth with disabilities, youth with medicated attention-deficit/hyperactivity disorder (ADHD) have the highest levels of STEM achievement, and youth with learning or intellectual disabilities typically have the lowest. Undergraduates with medicated ADHD or autism appear to be more likely to major in STEM than youth without cognitive disabilities, and youth with autism have the most positive STEM attitudes. Finally, results suggest that high school STEM achievement is more salient for college enrollment than STEM-positive attitudes across youth with most disability types, whereas attitudes are more salient than achievement for choosing a STEM major.