Glass fiber materials play a vital role in numerous industries, from construction to transportation and beyond. However, the increasing production and usage of glass fiber composites pose significant challenges, particularly in managing waste and achieving sustainability. Circular economy principles offer a promising solution by minimizing waste and maximizing resource efficiency. This report draws insights from the GlassCircle project, a multi-stakeholder initiative aimed at advancing sustainability in the glass fiber industry. Through events such as hackathons, workshops, and conferences, the project has successfully engaged industry leaders, academics, policymakers, and society in promoting circularity and innovation. The project was done within the Interreg Baltic Sea Region call co-funded by the European Union.