The Gabrielian Assessment and Proficiency System (GAPS) is a web-based certification platform developed for the College of Computer Studies mentors at Colegio de San Gabriel Arcangel, Inc. The system is designed to assess, certify, and ensure the proficiency, merit, and fitness of mentors in their respective major subjects. Its primary objective is to provide a comprehensive evaluation of mentors' subject knowledge, helping the school identify individuals who are qualified to teach their assigned courses. The target participants are the college mentors of the College of Computer Studies at Colegio de San Gabriel Arcangel, Inc. The system allows mentors to independently take certification exams, receive immediate results, and identify areas where improvement is needed. Administrators and deans can upload and assign exams, assess mentor performance, and use the system to monitor and support continuous development. The study conducted to assess the system's usability, efficiency, functionality, reliability, and overall effectiveness showed strong positive feedback from respondents, with weighted means of 4.6 out of 5.0 for most attributes. This highlights the system's success in meeting the needs of both mentors and administrators. GAPS aims to strengthen academic standards by promoting proficiency and ensuring that mentors are equipped with the necessary knowledge to deliver quality education. The system serves as an effective tool for improving the qualifications of mentors, supporting both their professional growth and the overall academic excellence of the institution. The experimental method of research was used in this study, the researchers used survey- questionnaires to gather information that may support the development of the system. The survey- questionnaires were distributed only to the college mentors of the College of Computer Studies at Colegio de San Gabriel Arcangel, Inc. The information entered into the instrument was drawn from ISO 9126 Standards for Evaluation of Software Quality particularly metrics on Functionality, Reliability, Usability, and Efficiency. The metrics for Portability and Maintainability were not included as these were hard to measure by the group of respondents. Overall, the respondents strongly agreed that the system was effective, efficient, and highly usable for the intended purpose.