The aim of this study is to investigate the Technology Pedagogy and Content Knowledge (TPACK) development of pre-service science teachers (PSTs) who participated in a TPACK Development Course (TPACK-DC) that consisted of three stages: a training course, lesson plans involving the application of micro-teaching, and school application. This study was carried out with six PSTs selected according to the appropriate sampling method. Semi-structured interviews, lesson plan reports, and video recordings of lesson presentations were used to follow the development of PSTs. At the end of the study, it was found that TPACK-DC contributed to the association of PSTs' Technological Knowledge (TK), Pedagogical Knowledge (PK), and Content Knowledge (CK), which eliminated deficiencies in these areas of knowledge, as well as in the understanding of TPACK. The TPACK-DC also promoted the use of information and communication technology (ICT) tools by PSTs. It helped to develop the knowledge required to choose suitable teaching methods using technology to teach the related subject matter, teaching said content correctly, applying skills to promote active participation by students, proper classroom management, and applying appropriate guidance while teaching science subjects with ICT tools.