This book constitutes the thoroughly refereed post-conference proceedings of the Third International Workshop on Higher Education Learning Methodologies and Technologies Online, HELMeTO 2021, held in Pisa, Italy, in September 2021. Due to the COVID-19 pandemic the conference was held online.  The 26 revised full papers and 3 short papers presented were carefully reviewed and selected from a total of 65 submissions. The papers present recent research on challenges of implementing emerging technology solution for online, online learning pedagogical frameworks, facing COVID19 emergency in higher education teaching and learning, online learning technologies in practice, online learning strategies and resources, etc.