This paper aims to discover the extensive potential of feedback in ESP/EAP teaching, specific for language teaching and applicable to academic courses at large. Teacher and peer feedback has been analyzed and systematized to identify principles, strategies and forms, which confirmed their effectiveness to support language and content learning and should be considered in course and curriculum development. The research methods applied were direct observation and analysis of conferences records, questionnaires of students and the faculty, and criterion-referenced performance tests. Presented here are the results of empirical studies of written feedback on students’ assignments, recorded and observed teacher-student/peer conferences where academic work was discussed and evaluated.