The present study sought to investigate factors influencing Iranian EFL teachers' adoption of Web 2.0 technologies in light of the unified theory of acceptance and use of technology (UTAUT) and technological pedagogical content knowledge (TPACK) theoretical frameworks. A hypothesized structural model consisting of seven pertinent constructs based on UTAUT and TPACK was proposed. The study composed a cohort of 160 EFL teachers from private language institutes, who completed a questionnaire designed to collect data on acceptance of Web 2.0. Data analysis was performed to test the proposed model via structural equation modeling. Findings of the study indicated that performance expectancy (PE) and social influence (SI) had positive and direct influences on behavioral intention (BI) to use Web 2.0 technologies, while effort expectancy (EE) and TPACK did not affect BI significantly. Facilitating conditions (FC) and BI had positive and direct effects on use behavior (UB). Moreover, TPACK influenced PE and EE significantly. The current study moves our understanding of technology acceptance one step further by considering the factors influencing EFL teachers' adoption of Web 2.0 in Iran.