The introspective, cognitive act of reflection is linked with professional growth for teachers (National Board for Professional Teaching Standards, 2010; National Council on Teaching America's Future, 2009; Learning Forward, 2009). However, current federal, state, and local mandates, policies, structures, and procedures in schools do not always mirror this knowledge or emphasize the need for teachers to be reflective. When teachers reflect on their classroom practices and student learning, they are better prepared to make adjustments and changes to meet their students' needs. Individual and collective reflection can yield greater results when structures within the school day support reflective practice. This study investigates teachers' perceptions regarding reflective practice and how principals can support this work. The research questions framing this work are: 1) How do teachers describe the role of reflection in their own professional learning and practice? 2) How do teachers describe their principal's role in supporting reflective practice? This qualitative study included 12 teacher participants from 3 demographically different high schools in one region of New York State. Findings included implications for principals regarding school-day structure, overt emphasis on reflective thinking, professional development, and professional learning communities. Findings also included recommendations for educational policy to restructure supports to assist schools in meeting state and federal mandates. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]