Identifying an appropriate class size is an important decision public schools face as they weigh balancing their budget with the impact class size may have on student achievement. This study examined perceptions of South Dakota kindergarten through third-grade teachers, elementary principals, and superintendents concerning optimal class size and the extent to which they felt the following factors influenced their optimal class size selection: classroom experience, class size research, financial implications, classroom management, and instructional quality. 97 superintendents, 73 elementary principals, and 264 elementary teachers in South Dakota were surveyed. Teachers provided significantly smaller optimal class size estimates for all grade levels (K-3) than principals and superintendents. Teachers, principals, and superintendents revealed class size research had little influence on their choice about optimal class size whereas instructional quality was identified as the most influential factor. Only superintendents identified financial implications to be a predominant factor influencing their optimal class size selection. This research reveals the discrepancies in perceptions among teachers, principals, and superintendents regarding optimal class size and the factors influencing their optimal class size selection. This information has the capacity to provide state governments and school leaders the insight needed to develop class size policies and professional development opportunities to build a common approach to addressing class size while reflecting on best practices identified in class size research.