<p>Metaverses enhance and intensify online interactions by seamlessly merging with physical experiences, unlocking a wide spectrum of opportunities and challenges. With the wider adoption of metaverses, diverse and dynamic platform ecosystems are expected to emerge. While these ecosystems hold significant potential for innovation and economic growth, they also raise ethical and societal challenges, thus highlighting the need for responsible governance. This paper addresses this need at the regional level. It focuses on the case of the European Union (EU) and its efforts to shape a vision for metaverse ecosystem governance. Drawing on stakeholder contributions from the EU’s open consultation and grounded in the Platform Assessment Framework (PAF), the study analyzes how responsibility is understood and managed in metaverse ecosystems. The findings show that responsibility in metaverse ecosystems must consider not only the needs of metaverse users, as emphasized by existing literature, but also those of other key actors, including platform owners and complementors. The paper proposes a framework for fostering responsible metaverse ecosystems through governance mechanisms, continuous monitoring, and design principles. It highlights that digital responsibility should consider both the development and diffusion phases of metaverse platforms. Moreover, it argues that ensuring responsibility in metaverse ecosystems should go beyond addressing societal implications and also aim at promoting market fairness.</p>