Introduction: The American Board of Orthodontics Objective Grading System (ABO-OGS) has established its validity, reliability and is a widely accepted objective index. A number of studies uses the Objective Grading System (OGS) to assess and compare the orthodontic treatment outcomes of universities and private practices. Also, to assess the efficiency of finishing protocols. Aim: The aim of the study was to use the ABO-OGS to assess the treatment outcomes of the orthodontic clinic program of the Suez Canal University over a period of five years (2017-2022). Materials and Methods: This retrospective observational study; with a total number of 122 unidentified post treatment casts and panoramic radiographic records that met the inclusion criteria was collected from the post graduate clinics of the Orthodontic Department, Faculty of Dentistry at Suez Canal University. Results: Patients with ABO-OGS pass score was (11.5%), borderline cases percentage was (21.3%), which represented almost (33 %) of the studied sample. While almost (67 %) of the total sample had a fail ABO-OGS score. Conclusion: There is increase in percentage of failed cases within the collected sample. This finding necessitate that the postgraduate clinicians should get orientation and calibration to both the ABO-OGS & The American Board of Orthodontics Discrepancy Index (ABO-DI), as a routine self-assessment method for better treatment outcomes.