The rapid climate change rate has drawn attention to controlling it within feasible limits. The goal has been set to control the average global temperature below 1.5 °C with respect to what it was before the pre-industrial level. Evaluating technology/product/process is necessary to know its environmental impact by life cycle assessment. This chapter introduces the history of development and definition of life cycle assessment. The International Standard Organization has set general guidelines for life cycle assessment. They include four essential steps. The transport sector is one of the major air-polluting sectors. The focus of the research community is to come up with greener solutions for the transport sector. Advanced vehicle technology, such as battery electric and hybrid electric vehicles, is being promoted as a better option than conventional vehicles. However, it is inappropriate to generalize the statement about any vehicle technology. Therefore, the use of life cycle assessment has come into practice to compare the environmental impact of different types of powertrains. Many factors, such as temperature, driving conditions, fuel processing, battery production, vehicle production, electricity generation, assembly, recycling, and disposal, contribute to the emissions that vary with vehicle technology and location. This chapter discusses in detail the energy and transportation scenarios, global warming, and climate change in the introduction section and later the methodology for conducting an LCA study on vehicles. Different types of fuel and vehicle cycle methods will help to distinguish between each other. The different types of life cycle assessment methods used for powertrains, factors affecting emissions, and some studies on vehicles in different countries are discussed.