The purpose of this study is to investigate teachers' perceptions of inquiry-based learning in middle school mathematics. The lack of literature related to inquiry-based learning in the middle school mathematics classroom creates a need for an investigation of its use, the various ways teachers incorporate it, and the possible barriers to using inquiry-based learning (IBL) on a regular basis. Due to the intent of this study being focused on teachers' perceptions, it was conducted using a qualitative methodology, with semi-structured interviews being used for data collection. Interviews were conducted to enable collection of data regarding the participants' understanding of and beliefs regarding IBL. Four major findings of this study resulted from the data analysis: (1) the shared definition of IBL is that it is a student-centered method of instruction, focused on real world mathematics that encouraged student engagement and collaboration; (2) teachers' instructional decisions were influenced by the achievement gap, their students' lack of mathematical perseverance, the amount of curriculum standards, and the state-mandated test; (3) IBL is considered to be an effective pedagogy, but there are stipulations that affect its effectiveness; (4) there is a need for specific training on IBL in mathematics. [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.]