Drawing on data collected during an evaluation of Indiana schools receiving Title I 1003(g) School Improvement Fund grants in the 2008-2009 school year, this article explores how professional development can be used to support school improvement efforts. This article upholds the conclusion that when activities support the development of a collaborative community of educators and the effective use of data, professional development can be a vital element of school improvement efforts. By engaging teachers as leaders and learners, professional development can help to ensure that school improvement efforts are embraced by all staff and to prevent teachers from feeling isolated during the school improvement process.