This study describes impairment in academic, interpersonal, recreational, and family financial or occupational domains across children in three mutually exclusive diagnostic groups: ever diagnosed with Tourette syndrome (TS), attention-deficit/hyperactivity disorder (ADHD), and both disorders. In 2014, parents reported on impairment and diagnostic status of children aged 4–17 years (n = 3014). Weighted analysis and pairwise t-tests showed more children with ADHD (with or without TS) experienced impairment in overall school performance, writing, and mathematics, relative to children with TS but not ADHD. More children with TS and ADHD had problematic handwriting relative to children with ADHD but not TS. More children with TS and ADHD had problematic interpersonal relationships relative to those with ADHD but not TS. Children with TS and ADHD had higher mean impairment across domains than children with either TS or ADHD. Findings suggest assessing disorder-specific contributions to impairment could inform targeted interventions for TS and ADHD.