<p>This Special Issue gathers research advances in modeling fuel cells fuel-cell-based hybrid power systems and green hydrogen production. It focuses on the methodologies for mathematical modeling by illustrating different aspects of fuel cell technology from system architecture to the hybridization level. In addition various applications (i.e. automotive stationary and cogeneration) and different fuel cell technologies (low and high temperature hydrogen- and methanol-fed) are addressed. The reprint is a valuable opportunity for those approaching the world of fuel cells as it offers a broad overview of the efforts that researchers are carrying out in this technology which is central to the road map of sustainable development.</p>