The significance of service-oriented architecture (SOA) in IT systems is its ability to create a modular framework for building and integrating software components as services. SOA allows for improved flexibility, scalability, and interoperability among services across different platforms and technologies. By enabling communication between diverse applications through standardized protocols, SOA facilitates easier maintenance and updates. Businesses can respond more rapidly to changing requirements, reduce development time, and enhance resource utilization, thus optimizing overall operational efficiency.