The purpose of this study was to determine factors that influence middle and high school students' use of public libraries, the type of materials they use, and the frequency with which students use public libraries compared to the students' use of school library media centers. A questionnaire was used as the data gathering instrument. It was conducted on site at three randomly selected DeKalb County (Georgia) library branches. Data were analyzed using the Statistical Package for the Social Sciences (SPSS) computer program. The study found that 58% of the students find needed materials in the public library. Only 22% indicated they find the materials they need in the school library media center. Parents and guardians were cited by 68% of the students as having the most influence on their public library behavior. Teachers were the most influential elements in the students' use of the school media center with media specialists having little influence on the students' library use behavior. The questionnaire is included in the appendix. (Contains 19 references.) (JLB)