Children with ADHD symptoms often display social competence deficits, yet mechanisms for their social difficulties remain unclear. Using data from the normative sample of non-intervention respondents (N = 387; 50% male; 49% non-European-American; age at initial assessment: M = 6.5 years, SD = 0.48) in the Fast Track project (Lochman and CPPRG "Journal of Consulting and Clinical Psychology" 63:549-59, 1995), the social-information processing ability of accessing responses for social situations was modeled across four time points from kindergarten to third grade. Teacher-rated aggression and ADHD symptoms were included as predictors of the intercept and slope. Low ADHD symptoms were associated with a decline in aggressive responses across childhood, whereas high ADHD symptoms were linked to an increase in aggressive responses that decelerated between second and third grade. Regarding competent responses, low ADHD symptoms predicted increases in competent responses, but this increase decelerated between second and third grade. High ADHD symptoms were also associated with a slight increase in competent responses into first grade, but competent responses decreased from first to third grade. Neither aggression nor the interaction of ADHD symptoms and aggression accounted for a significant amount of variance in aggressive or competent responses. Future research should identify if differences in response access associated with high and low ADHD symptoms link to difficulties making and keeping friendships.