Spelling is an important skill that is crucial to effective written communication. In this study, brief experimental analysis procedures were used to examine spelling instruction strategies (e.g., whole word correction; word study strategy; positive practice; and cover, copy, and compare) for four students. In addition, an extended analysis was used to determine the effectiveness of the selected strategy over time. Third- and fifth-grade students, who were identified by their teachers as being poor spellers, participated in individual sessions using various strategies to improve their spelling performance. The results of the brief experimental analysis were used to identify the two most effective strategies for each student, and those strategies were alternated during the extended analysis for comparison. All students showed spelling improvements; however, not all students responded to the same interventions. For all students, the extended analysis demonstrated results consistent with the original brief experimental analysis. Future research directions and implications for practice are discussed.