This document summarizes a workshop on interoperability among assistive technologies (ATs) and mainstream information and communication technologies. The workshop covered basic concepts of interoperability, current mainstream technologies, issues with the current landscape, and visions for the future. Interoperability allows ATs and user devices to communicate and work together at both the application and operating system levels. Currently, there are problems with accessibility architecture, compatibility between versions, and semantic interpretation of applications. The workshop proposed a universal interoperability API to maximize compatibility and reduce costs by facilitating efficient use of AT and device functions. Long-term, ubiquitous ATs delivered as a cloud-based service was envisioned.