This open access book constitutes the proceedings of the 9th European MOOCs Stakeholders Summit, EMOOCs 2025, which took place in Paris, France, during June 30-July 2, 2025. The 20 full papers included in this book were carefully reviewed and selected from 79 submissions. They deal with the ongoing transformation and critical challenges in online education — particularly in the context of artificial intelligence (AI) and sustainable lifelong learning.