The purpose of this study is to investigate differences between traditional conventional professional development and high quality reflective professional development and curriculum implementation of classroom practices. This study examined the extent to which professional development activities were associated with increased levels of curriculum implementation. Differences in curriculum implementation, teacher knowledge, and changes to teaching practice based upon the type of professional development that teachers have experienced were a focus of this study. A sample of 132 prekindergarten teachers engaged in implementation of a newly adopted curriculum, High Scope, participated in the study. Professional development was provided for two consecutive academic years (2010-2011 and 2011-2012). Traditional professional development (lecture, large group, lower frequency, and no active participation) was provided during the first year. The second year, teachers participated in reform professional development programs (smaller groups, one location, consistent presenter, immediate on-going feedback/support, cohort/team approach, interaction, and a higher frequency of training sessions). Teachers completed a survey of the final day of the reform professional development session at the end of the 2012 school year. The findings were consistent with studies of significant professional development and the teachers' conclusions about how effective specific types of training influenced their understanding and implementing of the curriculum. The findings further supported the significance of immediate feedback and consequently the on-going classroom, phone, text, email, and other means of support for promoting the High Scope curriculum implementation in the prekindergarten classroom. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]