Orthographic knowledge of alphabet-letters is thought to mediate accurate motor execution of letter-writing. This study examined the effectiveness of a handwriting program for early non-proficient writers which integrated instruction of factual, procedural, and spatial information to develop orthographic knowledge of alphabet-letters, for the purpose of mastering alphabet-letter writing skills. A non-concurrent ABA single system research design was employed. The A phases represented in-class handwriting instruction and the B phase was the experimental intervention. Participants were ten children in their first two years of formal schooling, identified by their teacher as having difficulty with handwriting. The repeated outcome measure was the Perceive, Recall, Plan and Perform System of Task Analysis (Stage One). Results indicated that changes to accuracy of letter-formation achieved during the experimental intervention, were significantly greater than during the initial baseline condition. All ten children displayed a similar pattern of results and achieved, on average, independence in writing the twenty-six-lowercase alphabet-letters from memory within six-weeks (nine hours) of intervention. Independence in writing alphabet-letters from memory was maintained when intervention was withdrawn. The study provided preliminary evidence that establishment of memory structures for the acquisition of orthographic knowledge of alphabet-letters, improves alphabet-letter-writing of children who previously struggled.