This study evaluates the in-service teacher training program: The Teaching Knowledge Test (TKT) in its early stage of implementation for the ESP teachers at the University of Gafsa, Tunisia. It mingles summative evaluation and formative one. In its end, it raises alarming concerns about the aptness of this training program for the ESP teachers at the University of Gafsa and revealed that it fell short of meeting their training needs and lightening the burden of the plethora of roles assigned to them. In the light of the obtained findings, some recommendations regarding the reinforcement and extension of the TKT training program are provided. Equally, this study provides some practical solutions to enhance the ESP teaching/learning in the Tunisian universities.