This chapter assesses the role of hydrogen as a decarbonisation vector for road and rail transport. It analyses key technological pathways—fuel cells, combustion engines, and hybrid systems—comparing their efficiency, cost, and infrastructure requirements against dominant alternatives like battery-electric vehicles and direct electrification. The analysis reveals a segmented future: for light-duty road transport, battery-electric vehicles (BEVs) are the unequivocal leader on efficiency, cost, and increasingly, reliability, confining hydrogen fuel cell vehicles (FCEVs) to a potential niche. In heavy-duty road transport, BEVs are increasingly competitive, but hydrogen may find a role in specific long-haul, high-utilisation niches, though its commercial fragility is evident. For rail, a clear hierarchy emerges: direct electrification is preferred, batteries are optimal for bridging non-electrified gaps, and hydrogen is reserved for the hardest-to-electrify corridors. The chapter concludes that hydrogen’s widespread adoption in transport is constrained by the overarching challenge of producing affordable, low-carbon hydrogen at scale, with its application being highly selective rather than universal.