IT maintenance is important for a company because these activities are carried out to maintain and support the optimal performance of a company's IT systems and infrastructure. Generally, selecting an IT maintenance vendor is done by collecting vendor data and then evaluating it based on the desired criteria. This, of course, results in the time it takes to make a choice and makes it difficult to determine the best option. If you choose the wrong IT maintenance vendor, it will result in disrupting the company's stability. This research was conducted with the aim of developing a decision support system that can be used to determine the IT maintenance vendor that best suits their needs and preferences using the WASPAS (Weighted Aggregated Sum Product Assessment) approach. This method is used to determine the best option through weighted addition and multiplication, producing a final value that reflects the extent to which each option can meet the specified criteria. From the existing case studies, the best alternative was obtained, namely: Microsis (A4) got a preference value of 0.8769, followed by ICT Canopy (A1) with a preference value of 0.8613, Pillar IT (A2) with a preference value of 0.8408, Indocom Niaga (A5) with a preference value of 0.8180, and Sasana Digital (A3) with a preference value of 0.7389. The usability test carried out received a score of 88%, which indicates that the system is suitable for use.