In this single-subject design study, we examined the effects of an intervention targeting planning and self-regulation strategy use on the persuasive writing of children with high-functioning autism spectrum disorders (ASD). Three 8- to 9-year-old children with ASD in third and fourth grades learned a mnemonic-based strategy for planning and writing a persuasive essay using the self-regulated strategy development (SRSD) approach. The intervention was provided by the students' special education teachers following 2 professional development sessions, accompanied by weekly consultation by the authors. Comparison of 3 persuasive essay baseline probes with 3 postintervention probes revealed increases in holistic quality for all 3 participants, with mean increases from 3.2 to 7.0, 3.4 to 7.0, and 2.7 to 6.5 respectively. Word length decreased for 1 participant and increased for 2 participants, indicating that essay length in words was not directly correlated to improvements in overall quality. Evidence of planning and self-regulation was noted for all 3 participants on all 3 posttest probes, whereas planning was not evident on any of the pretest probes. Results of calculating the percentage of nonoverlapping data points from pre-/posttest holistic scores showed 100% posttest scores exceeding lowest baseline scores; this fell above the 90% effect-size threshold, providing evidence for the SRSD approach using POW + TREE as a "very effective" treatment option for improving the persuasive writing skills of students with high-functioning ASD. This study also showed that special education teachers could learn to implement the intervention with fidelity with limited training and consultation.