Interoperability is increasingly becoming a focus point for organizations that distribute and share data over the Internet. The Open Geospatial Consortium (OGC) focuses on the development of publicly available geospatial web standards. UMN MapServer currently supports numerous OGC specifications, allowing users to publish their data services in an interoperable manner. This workshop will review the OGC specs supported in MapServer as well as provide information on implementation options and issues, as well as what the future holds for OGC support in MapServer.