This quantitative study was conducted in one high-performing, suburban school district and examined the beliefs of 94 secondary science teachers as they relate to inquiry-based instruction and their use of the approach. The study rests on Fives and Buehl's integrative teacher belief framework (2012) which was developed from an exhaustive review of empirical teacher belief research. A modified version of DiBiase and McDonald's (2015) teacher belief survey was used and measured teachers' understanding and use of inquiry-based instruction, beliefs about the approach, instructional priorities, and concerns related to implementation of the approach. Research questions included: 1) What are teachers' beliefs about inquiry-based instruction? 2) What factors are related to teachers' beliefs about inquiry-based instruction? 3) How are secondary science teachers' beliefs about science and inquiry instruction related to their use of inquiry instruction? 4) How are teacher beliefs about their school and community context related to their use of inquiry instruction? Findings showed that despite decades of reform efforts advocating inquiry practices, teachers still have limited understanding of inquiry or how to enact it in their own classrooms. Limited understanding was associated with classroom management and accountability concerns. Teachers were especially concerned the approach was inadequate preparation for future science courses and college. Overall, participants held positive views of inquiry and believed it enhances learning but not equally for all students. Inquiry beliefs were not significantly influenced by perceptions of principal or school wide support for the practice. While teachers view inquiry favorably, there is a clear need for experiential training to build understanding and address concerns. [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.]