The transportation fuel sector is under pressure to reduce its greenhouse gas (GHG) emissions as a result of low-carbon fuel standards (LCFSs), which have been passed by the State of California and the European Union. These standards will be particularly challenging for producers of oil sands, heavy oil, and other unconventional resources. Oxyfiring with CO2 capture is a promising technology for reducing CO2 emissions from the transportation fuel sector, but it requires a significant amount of energy to generate oxygen. This study examines the potential for oxyfiring to reduce life-cycle GHG emissions from transportation fuels derived from in situ and ex situ oil shale and ex situ oil sands in the Uinta Basin of Utah. It also examines the effect of oxyfiring with CO2 capture on the net energy return (NER). The evaluation focuses on the fuel’s life-cycle GHG emissions, and it includes resource extraction, upgrading, transportation and refining. The results suggest that oxyfiring could help some unconventional sources of crude oil, such as ex situ production of oil sands and oil shale, meet a LCFS. However, oxyfiring with CO2 capture reduces NER.