Identifying significant factors in teaching-learning performance affecting the efficiency of teachers at university is an indispensable factor in upholding the quality of the teaching in English for Academic Purposes (EAP) courses. This study aims to evaluate teachers' performance in EAP courses using the students' course-instructor evaluation survey, and the students' final grades. For this purpose, the Performance Improvement Management (PIM) software Data Envelopment Analysis (PIM-DEA) is applied to evaluate the efficiency of EAP teachers. Later, a sensitivity analysis is applied to prioritize the significant indicators of teacher performance following an interview with the teachers aimed at the betterment of their performance. The result of the study reveals that the degree of student satisfaction in relation to assignments, exams, and grading systems are significant factors related to teachers' performance. A wider realization of this should be seen, in the researcher's opinion, vital to the development of the educational sector.