Over recent years, the teaching profession has undergone major changes and, consequently, a great deal of instability. Assessment has emerged as a strategy to regulate and enhance teaching, and as a result, various educational reforms have been introduced in pursuit of effective and appropriate assessment. Given the importance of the relationship between the teacher being assessed and their assessor, who is responsible for monitoring the assessed teacher's professional development and with whom they must maintain constant interaction, supervisory interaction is extremely important for the assessment objectives to be achieved. This book presents an analysis of the concepts of supervision and the supervisory relationship in the context of teacher performance evaluation, with a special focus on discourse and styles of supervision. The study published here was produced as part of the Master's Degree in Education Sciences - Specialisation in Pedagogical Supervision in Language Education at the University of Minho.