This study examined patterns of change in the science teaching practice, beliefs, and content knowledge of 15 upper-elementary teachers from three Title I schools during their participation in a yearlong, reform-based science professional development program and during the year following the program. Further, this study sought to understand the school factors that hindered or supported these patterns in the year following the program. This study responds to calls for research on understanding teachers' continued learning within the context of their classroom and school environment following professional development experiences. A mixed model design, integrating quantitative and qualitative data, was used. Quantitative data were used to examine changes in teachers' practices, beliefs, and physical science content knowledge across the 2 study years. Qualitative data were used to corroborate this data and provide additional insights into observed patterns. Both data types were used collaboratively to understand the barriers and supports in teachers' schools to their continued learning following professional development. The study findings indicated that scores in all three measures increased a statistically significant amount in Year 1. Scores continued to increase in Year 2, but only content knowledge scores increased significantly. Qualitative data corroborated the survey findings in teachers' beliefs and practices. A combination of school- and individual-level factors impacted the Year 2 changes. School-level factors were: (a) supportive same-grade teams and/or a mentor who advocated inquiry science and prioritized science as a subject, (b) principal prioritization of science, and (c) easy access to and training in the use of relevant materials. The individual-level factor was teachers' degree of willingness and readiness to change their beliefs in fundamental ways. The study results suggested that professional development, along with school and personal factors, impacted teacher change. These findings inform the education literature bases as well as professional development providers and school administrators about the types of support and resources that teachers require in the school context in order to maintain or enhance professional development experiences. The decisions teachers make about whether and how to implement and sustain new practices, and the reasons for these decisions, ultimately determine the success of reform-based professional development in science education. [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/en-US/products/dissertations/individuals.shtml.]