Objective: This trial compared attention-deficit/hyperactivity disorder (ADHD) treatment alone, intensive reading intervention alone, and their combination for children with ADHD and word reading difficulties and disabilities (RD). Method: Children (n = 216; predominantly African American males) in Grades 2–5 with ADHD and word reading/decoding deficits were randomized to ADHD treatment (medication + parent training), reading treatment (reading instruction), or combined ADHD + reading treatment. Outcomes were parent and teacher ADHD ratings and measures of word reading/decoding. Analyses utilized a mixed models covariate-adjusted gain score approach with posttest regressed onto pretest. Results: Inattention and hyperactivity/impulsivity outcomes were significantly better in the ADHD (parent Hedges’s g = .87/.75; teacher g = .67/.50) and combined (parent g = 1.06/.95; teacher g = .36/41) treatment groups than reading treatment alone; the ADHD and Combined groups did not differ significantly (parent g = .19/.20; teacher g = .31/.09). Word reading and decoding outcomes were significantly better in the reading (word reading g = .23; decoding g = .39) and combined (word reading g = .32; decoding g = .39) treatment groups than ADHD treatment alone; reading and combined groups did not differ (word reading g = .09; decoding g = .00). Significant group differences were maintained at the 3- to 5-month follow-up on all outcomes except word reading. Conclusions: Children with ADHD and RD benefit from specific treatment of each disorder. ADHD treatment is associated with more improvement in ADHD symptoms than RD treatment, and reading instruction is associated with better word reading and decoding outcomes than ADHD treatment. The additive value of combining treatments was not significant within disorder, but the combination allows treating both disorders simultaneously.