The profound consequences of early reading failure necessitate the provision of early literacy interventions to struggling readers. Many schools struggle, however, to address early reading difficulties because of insufficient human resources. Accordingly, the present study investigated the effectiveness of incremental rehearsal (IR) as a Tier 3 intervention to improve letter sound knowledge and fluency with four kindergarten students. Four participants not making adequate progress toward letter sound fluency benchmarks were selected for an IR intervention targeting letter sounds that was delivered via a computerized tutoring program. All four students improved their letter sound knowledge and fluency. Overall, results indicated that a computer-aided IR intervention is an effective, efficient, and acceptable intervention. Implications for research and practice are discussed. (Contains 3 figures and 1 table.)