Despite the expanding data streamon the importance of ESP teaching in EFL education worldwide, relatively little attention has been paid to the EFL teachers’ beliefs and understanding about the pedagogy related to ESP. In the Tunisian context, there are some calls to focus on this particular concern to boost practitioners' awareness and professional development. Thus, this exploratory study focused on tracing EFL teachers’ philosophy of teaching ESP in the tertiary Tunisian system. to identify their previous knowledge and experience. The data was gathered over a period of two months. Data analysis provided support for the challenges faced by the teachers in approaching ESP teaching that parallel the ones found in the literature on teacher change and teacher cognition. In light of the findings, the researcher recommends that ESP teacher educators focus on adopting a reflective model of training in order to boost teacher development and schema change in relation to the existing challenges identified in this study.