Because of greenhouse gas (GHG) emissions, climate change mitigation requires the deep and accelerated decarbonisation of the transport sector. Yet this area has received little political attention, particularly in emerging economies like Mexico. This policy paper examines the GHG emissions of Mexico’s transport sector and its medium-term trends, providing a critical perspective on the sector’s mitigation policies based on a national and sectoral carbon budget. It also provides input to the growing debate in Mexico on how mitigation action in the transport sector could be enhanced and adds to the ongoing debates carried out by different stakeholders.