Problem Statement: Based on developments in the 21st century technology has become a large part of the classroom experience. Teachers need to have an understanding of how technology can be coordinated with pedagogy and content knowledge in order to integrate technology effectively into classroom instruction. Self-efficacy beliefs toward technology also play a key role in technology integration. It has been shown that the beliefs of a teacher are closely linked to the technologies that they use and the way in which they use them. More specifically, the beliefs of a teacher with regards to their technological pedagogical content knowledge (TPACK) are pivotal in terms of using technology in the classroom because belief about their capability to use technology is a powerful predictor of their potential technology use. Hence, it is critical to measure pre-service teachers' self-efficacy beliefs toward TPACK in order to identify the factors that contribute to a teacher's use of technology in classroom instruction. Purpose of this Study: The purpose of this study is to develop a comprehensive instrument to determine pre-service science teacher's self-efficacy beliefs towards TPACK Methods: The participants in the study consisted of 808 senior pre-service science teachers in 17 colleges for teacher education. In this study, the data was split into two random subsamples to perform factor analysis. Exploratory Factor Analysis (EFA) was conducted using one subsample (n = 420) to determine the factorial structure of the scale, and Confirmatory Factor Analysis (CFA) was conducted on the second subsample (n = 388) in order to confirm the structure model obtained from the EFA analysis in cross-validation the Technological Pedagogical Content Knowledge Self-Efficacy Scale (TPACK-SeS) for a different sample. Item total correlations and Cronbach's alpha internal reliability coefficient were utilized in determining the reliability of the whole scale and its subscales for both samples. Findings and Results: Based on the EFA results, the final version of the scale consists of an eight-factor structure with 52 items. Following EFA, CFA supported this eight-factor structure and showed a good fit with high indices. Cronbach's alpha coefficient, demonstrating the internal consistency reliability of the subscales and whole scale, were found to be high, and item total correlation coefficients were valid for the different samples. Conclusions and Recommendations: The results show that TPACK-SeS can serve as a valuable tool for teachers, educators, and researchers in evaluating pre-service science teacher's self-efficacy beliefs towards TPACK.