Diminished response to name, a potential early marker of autism spectrum disorder (ASD), may also indicate risk for other disorders characterized by attention problems, including attention-deficit/hyperactivity disorder (ADHD). Using a familial risk design, we examined whether response to name ability at 6, 12, 18, 24, and 36 months of age differed between three 36-month outcome groups: ASD, ADHD Concerns, or a Comparison group. Persistent differences between the ASD and Comparison groups were evident beginning at 12 months; differences between the ADHD Concerns and Comparison groups were evident between 12 and 18 months only. Results suggest that response to name may be a general marker for ASD and ADHD risk in infancy but a specific indicator of ASD by 24-months.