The aim of this study is to investigate the practice of educational supervisors of practical lessons as a supervisory approach and its relation to improve teachers' professional performance in schools in the Sultanate of Oman. The study relied on the descriptive approach using a qualitative data ( A case Study). To achieve the study's aims, the researcher used interviews as the main qualitative tool in collecting her data. The interview consisted of four main questions and targeted a sample of 6 participants who were mainly educational supervisors and teachers in (5-10) schools in Al Dakheliya Governorate. The study results showed a positive relation between supervisors practicing practical lessons in their supervision and the improvement of teachers' professional performance. Another result revealed the importance of using practical lessons by supervisors in their supervision as a way to diversify supervisory methods, and how it could have a great impact on the teachers' professional growth. This growth was indicated in the lesson preparation, classroom management, teaching methods and assessment tools and techniques. Moreover, the study revealed that supervisors might face some challenges and difficulties when using practical lessons. It recommended the necessity of handling these challenges and difficulties to reach their high expectations. It also recommended to design a complete guide of how to apply practical lessons and encouraged supervisors to join professional training programs. It suggested enrolling supervisors continuously at "The Specialized Center for Professional Training of Teachers" to take similar courses. Finally, the study recommended supervisors to include practical lessons in their professional development plan. It suggested that supervisors should consider practical lessons as an essential supervisory approach and they should plan for them by the beginning of the Academic year.