Data-driven decision making (DDDM) is an important teaching practice that can positively influence student achievement by using assessment data to make instructional decisions. The problem is that teachers do not always use this practice. Teachers' perspectives of DDDM can influence their data use practices. This basic qualitative study was conducted to explore teachers' perspectives on using data for instructional decision making. The conceptual framework used was the theory of planned behavior. Participants included 11 teachers from a district in the Northeastern United States, with at least 3 years of teaching experience. Semistructured interviews were used to answer the research question about teachers' perspectives on using data for instructional decision making. Data analysis included open, axial, and selective coding using thematic analysis. Four themes were identified from the data analysis: (a) administrative support structures influence teachers' DDDM practices, (b) a variety of data and data literacy skills are necessary for DDDM, (c) teachers express negative attitudes toward schoolwide DDDM expectations and data use for teacher evaluations, and (d) teachers express confidence regarding the benefits of DDDM and in their ability to use data for instructional decision making. Recommendations for future research included the efficacy of schools' DDDM professional development, investigating the accessibility of non-academic data for teachers, and comparing teachers' confidence with their DDDM efficacy. The results of this study may contribute to positive social change by providing information that school leaders and teachers might use to improve DDDM and student academic achievement. [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.]