This article discusses the use of data-based feedback and support to teachers in Head Start classrooms to facilitate increased use of effective instructional and managerial practices. The authors conducted a study to examine the impact of providing Head Start preschool classroom teachers with data regarding their use of established instructional and managerial practices, encouraging teacher self-selection of goals for improvement, and giving ongoing feedback and support related to goal attainment. Although the individual teacher outcomes varied, the results suggest that professional development accompanied by data-based individualized teacher feedback and support can improve teacher use of effective instructional strategies. Strengths, challenges, and implications for Head Start teachers are discussed. (Contains 1 table.)