This research aimed to investigate the self-perceived competency levels of EFL teachers in the Turkish MONE (Ministry of National Education) context and if these perceptions vary according to multiple variables as a mixed-methods study. Another subject of the study was to identify the areas where teachers see themselves as less competent and need professional development. In doing so, the English Teachers Field-Specific Competencies Assessment Scale was applied to 267 English teachers by snowball sampling via an online survey. Simultaneously, 27 English teachers filled out written interview forms prepared by the researchers to obtain in-depth knowledge. Then, the data were analyzed with the convergent parallel design method, and the qualitative and quantitative data thus complemented each other. The main results indicated that participants were uncertain about their professional skills in teaching English to students with special needs. It was also revealed that teachers had similar views on improving students' English-speaking abilities. Another finding was that education level, professional experience, and participation in previous in-service teacher training programs statistically affect teachers' self-perceived competency levels. In brief, it was understood that developing language skills, specifically speaking skills, was the most common need, followed by the demand to develop EFL teachers' digital skills.