Today, it is of great importance that teachers have pedagogical and technological knowledge in addition to content knowledge. For this reason, the present study aims to develop a TPACK self-efficacy scale for preservice science teachers by following the theoretical framework of technological pedagogical and content knowledge (TPACK), as suggested by Koehler and Mishra (2006). The scale consists of seven subscales, which are technology knowledge (TK), pedagogy knowledge (PK), content knowledge (CK), technological pedagogical knowledge (TPK), technological content knowledge (TCK), pedagogical content knowledge (PCK), and technological pedagogical content knowledge (TPCK) with a total of 55 items. A total of 467 preservice science teachers from four different universities in Turkey participated in the study. The Cronbach's alpha reliability coefficient of the scale was calculated as 0.969. Following the modification suggestions, confirmatory factor analyses showed that the model fit the scale adequately. The study found significant differences between the bottom and top groups; this shows the sufficiency of the items' discriminatory powers. As the result of these analyses, it was found out that the scale had the necessary properties required for measuring the TPACK self-efficacy perceptions of preservice science teachers.