This study explores the energy security implications of possible development pathways of the transport sector. It proposes a framework to systemically assess energy security in the transport sector and the national/regional energy security in China, India, Japan, USA and the EU in nine scenarios of short-term future. The main findings are as follows. First, energy security of the transport sector is closely related to national energy security, but this relation is complex. The rapid growth of energy demand in the transport sector prominently affects national energy security. But for industrialized countries where efficiency gains in the transport sector have mostly been exhausted, suppressing the transport sector does not produce apparent contribution to national energy security. Diversity in the transport sector is also closely related to overall diversity. Import dependence of the transport sector seriously affects overall import dependency of industrialized countries. To reduce import dependence, industrialized countries benefit the most from supply-side approaches, such as diversification of primary energy sources, while developing countries benefit the most from the efficiency improvement. Secondly, in the short-term, different development scenarios result in trade-offs between reducing import dependency and controlling demand growth. Thirdly, the climate neutral scenario and the Mix scenarios (which emphasis diversity in policy choices) are the most energy secure scenarios in the analysis. Important factors in improving energy security in both the transport sector and national energy systems include ensuring flexibility of policy choices and balance between supply-side and demand-side interventions, and promotion of technological development in the transport sector.