The purpose of this study was to investigate the effectiveness of implementing the Self-Regulated Strategy Development (SRSD) model of instruction (Graham & Harris, 2005 ; Harris & Graham, 1996 ) on the writing skills and knowledge of six first grade students. A multiple-baseline design across participants with multiple probes (Kazdin, 2010 ) was used to test the effectiveness of the SRSD intervention, which included story writing and self-regulation strategy instruction. All students wrote stories in response to picture prompts during the baseline, instruction, post-instruction, and maintenance phases and stories were assessed for essential story components, length, and overall quality. Participants also participated in brief interviews during the baseline and post-instruction phases. Results indicated that SRSD can be beneficial for first grade writers. Participants wrote stories that contained more essential components, were longer, and of better quality after SRSD instruction. Participants also showed improvement in writing knowledge from pre- to post-instruction.