Background: Only half of US schoolchildren receive influenza vaccine. School-located influenza vaccination (SLIV) might raise vaccination rates but conducting flu vaccine clinics at schools is challenging to implement. We compared 2 school-based programs designed to raise influenza vaccination rates: parent reminder/educational messages sent to parents from schools which is a low-intensity intervention vs the combination of reminder/educational messages plus SLIV clinics which is a high-intensity intervention. Methods: We assigned 36 schools (6 school districts, 2 per group) to 3 groups: (1) control, ie, no SLIV and no parent reminder/education, (2) parent reminder/education emailed by schools, and (3) parent reminder/education plus SLIV clinics. Some schools had SLIV clinics in prior years. Health department nurses conducted SLIV clinics. Results: Among 24,832 children at 36 schools, vaccination rates were control (51.3%), parent reminder/education-only (41.2%), and reminder/education + SLIV (58.7%). On multivariate analyses which controlled for vaccination in prior seasons, children in reminder/education + SLIV schools had higher vaccination rates (OR 1.27, 95% CI 1.10-1.47), but children in reminder/education-only schools had lower rates (OR 0.87, 95% CI 0.75-1.00) than children in control schools. Conclusions: Parent reminder/education combined with SLIV clinics raise vaccination rates, but parent reminder/education alone does not.