In the present study, we sought to examine response trajectories to brief (11-week) school-based homework interventions and factors that may help schools predict responses. Participants included 222 middle-school students (72% boys; M[subscript age] = 12.00 years, SD = 1.02) who had been diagnosed with attention-deficit/hyperactivity disorder (ADHD) and had received either a contingency-management or skills-based intervention for homework problems. Both interventions included 16 20-min student meetings with a school counselor and two parent meetings. Trajectories of response for ratings of homework problems and assignment completion were examined from baseline to a 6-month follow-up using growth-mixture models. Baseline variables routinely measured in school settings, including grade-point average (GPA), math and reading achievement, and externalizing and internalizing symptoms, were examined as predictors of treatment-response trajectories. The majority of students (68-81%) showed positive treatment response across outcomes. However, trajectories of students who did not respond to intervention were identified for each outcome. Baseline GPA significantly predicted trajectories for all outcomes and achievement scores significantly predicted trajectories of teacher-reported homework performance and parent-reported homework problems, such that youth with relatively higher baseline GPAs and achievement were most likely to respond. In contrast, neither externalizing nor internalizing symptoms were significant predictors of response trajectories. Schools can use GPA and academic-achievement data to determine whether brief school-based interventions for homework problems are likely to succeed. Students with ADHD who display severe academic impairment (i.e., GPA lower than 2.0 at baseline) may benefit from a more long-term, intensive intervention.