This exploratory study investigated the relationship between measures of Technological Pedagogical Content Knowledge (TPACK) and the self-efficacy beliefs of preservice teachers about technology integration. Within a single-group, pretest-posttest design, a correlational analysis identified several knowledge domains in the TPACK model that the researcher found to have a significant and positive correlation with self-efficacy beliefs about technology integration. A multiple regression analysis of pretest and posttest data indicated a change over time in the predictive relationship between the measures of knowledge in TPACK domains and self-efficacy beliefs. Findings from the study illustrate the changing nature of the complex relationship between knowledge and self-efficacy beliefs and highlight the potential areas of knowledge in TPACK domains that influence preservice teachers' beliefs about technology integration. (Contains 1 figure and 6 tables.)