Writing is a tool students with autism spectrum disorder (ASD) can use to communicate and interact with other people socially and professionally. Strong writing skills may lead to social and economic success, as well as a sense of self-empowerment. Unfortunately, there is very little research related to the use of sentence-writing strategies and self-monitoring procedures to improve the writing performance of adolescent students with ASD. Thus, this study was designed to examine the effects of a sentence-writing strategy and a self-monitoring procedure on the writing performance of adolescents with ASD. The study included five participants. These participants attended the same junior high school in a large southwestern city and were in the sixth, seventh, or eighth grade. Each participant had a spectrum disorder. A multiple baseline across participants design with one replication was used in this research. There were three conditions in this design: baseline, Intervention 1: sentence writing strategy, Intervention 2: self-monitoring procedure, and Maintenance. A comparison of curriculum-based probes between phases was conducted in order to assess the functional relationship between the independent and dependent variables. The independent variables were The Proficiency in Sentence Writing Strategy (Schumaker & Sheldon, 1999) and the self-monitoring procedure. The dependent variables were writing quality and writing quantity. Writing quality was measured using specific predictive indicators for writing quality and criterion described in the Proficiency in Sentence Writing Strategy Instructor's Manual (Schumaker & Sheldon, 2006). Writing quantity was measured by counting the total number of words written during each session. A visual analysis of the data revealed five things. First, each participant responded differently to the sentence writing strategy and the self-monitoring procedure. Second, when the interventions were combined, a moderate effect size resulted. Third, participants' feelings about writing may have influenced performance levels. Fourth, all the participants ended the study feeling better about their own writing ability, and fifth, the sentence writing strategy and the self-monitoring procedure are socially valid interventions that may improve the overall writing performance levels of middle school students with ASD. These findings support the use of The Proficiency in Sentence Writing strategy and the self-monitoring procedure in middle schools and classrooms where middle school age students with ASD are receiving writing instruction. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]