Service-oriented architectures facilitate distributed business processes where multiple services collaborate to achieve business goals. However, traditional process mining approaches rely on single-case event logs that fail to capture the complex interactions between services and their associated data objects. Object-Centric Event Logs (OCELs) address this challenge by modeling service processes as graphs of interconnected events and objects, providing a foundation for comprehensive service analysis. While existing querying approaches offer capabilities for traditional event data, they lack the expressiveness needed for analyzing object-centric service interactions. This paper introduces GOProQ, a graphical query language specifically designed for querying object-centric service processes. We identify key requirements for service-oriented process querying, define a formal language that addresses these requirements, and implement an interactive tool for service analysts. Our evaluation across multiple real-world service datasets demonstrates GOProQ’s expressiveness and performance for service monitoring in complex service-oriented environments.