Improving on‐task behavior can allow individuals to access more learning opportunities and is especially relevant for individuals with developmental disabilities. The current study examined the efficacy of an intervention package that used percentile schedule of reinforcement, feedback, and application of lower limits to changes in criteria to increase on‐task behaviors in children with developmental disabilities. Using a nonconcurrent multiple baseline across participants design, data revealed a functional relationship between the implementation of the intervention and an increase in the percentage of intervals that participants were on task. Overall, the participants' on‐task behavior improved from a mean of 32% during baseline to 68% during intervention, with a proportionate percentage change of 118%. Although there is no widely accepted method for shaping, using percentile schedules as part of an intervention package appears to be a promising way to shape behavior.