The recent advancement of digital technologies has triggered a prominent shift within the field of language education. Considering the teachers' vital roles in adopting modern instructional technologies, this study investigates in-service EFL teachers' TPACK self-efficacy levels, explores the relationship between their TPACK self-efficacy levels and their demographic features and perceptions towards Web 2.0 technologies. Employing a mixed method design, the study collected quantitative and qualitative data in two phases. The quantitative data was collected through an online survey with 227 EFL teachers from various schools. Following the first phase, seven voluntary teachers were interviewed. The findings suggested that participants had a high level of content knowledge, pedagogical content knowledge and pedagogical knowledge, but they reported a relatively low level of self-esteem when the knowledge of technology was included. Furthermore, statistically significant differences were found between the teachers' TPACK self-efficacy levels and their educational level, school type, perceived digital literacy levels and previous INSET experience on Web 2.0 technologies. A positive and high level of correlation between TPACK self-efficacy of EFL teachers and their Web 2.0 self-perceptions was also reported. Semi-structured interviews demonstrated that despite their favorable perceptions towards Web 2.0 technologies, EFL teachers do not amply utilize Web 2.0 tools in teaching mainly due to their inadequate technological and technological pedagogical knowledge.