This study discusses the design and development of a web-based alumni data management information system at STMIK Widuri. The rapid development of information technology has encouraged educational institutions to improve the quality of information services and data management systems. One of the important data that must be managed properly by universities is alumni data, which is useful for administrative needs, accreditation, tracer study activities, and communication between the institution and alumni. However, the alumni data management process at STMIK Widuri is still carried out manually, causing several problems such as difficulties in data searching, delays in report generation, data duplication, and the risk of data loss. This research aims to develop a web-based information system that can facilitate alumni data processing, updating, searching, and reporting activities effectively and efficiently. The research method used in this study is the Waterfall method, which consists of requirement analysis, system design, implementation, testing, and maintenance stages. The system was developed using PHP as the programming language and MySQL as the database management system. The results of this study indicate that the developed system can improve the effectiveness and efficiency of alumni data management, simplify data processing activities, improve data accuracy, and provide easier access to information for administrators and alumni through an online platform.