Data-driven decision-making (DDDM) in public K-12 education is a concept that has been studied extensively over the last 20 years. Using data to inform or make decisions is believed to be an important and valuable strategic process. This exploratory, descriptive research focused on public school principals and their use of data in their decision-making process, particularly when those decisions involve instructional practice and student achievement. The research questions sought to understand school principals' views of DDDM, what types of data principals use and how principals use those data to make decisions, and what factors may have facilitated or hindered principals' use of data. To answer the study's research questions, principals in a southeastern state were invited to respond to a survey designed to collect data regarding the respondent's data-related attitudes and beliefs, and their actual data use as well as their demographic background and professional experience. Even though the small sample size limits the ability to generalize the results, the results confirmed what previous studies found, such as school districts and principals' expectation of using data for decision-making, the importance of data, and that principals needed more time to thoroughly review all the data they had access to. The study reveals a need to continue providing principals with the time and supports needed to use and analyze data. Generalizing the results should be done with caution because of the small number of responses, but the demographics of the survey respondents matched those of the southeastern state and nationally. [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.]