The global demand for energy, driven by the growing human population and industrial advancements, coupled with depleting fossil fuel reserves, has increased the search for alternative, sustainable energy sources. Oilseed crops are cultivated worldwide due to their role in the human diet and the wide range of industrial applications of their seeds. As a result, the disposal of large volumes of oilseed biomass generated after processing and harvesting poses a significant challenge for waste management and environmental sustainability. On the contrary, this biomass also presents a potentially sustainable and renewable source for bioenergy production. Oilseed biomass residue can be transformed into bioenergy such as biogas, bioethanol, biohydrogen, and bio-oil through biological and thermochemical methods. The transformation of oilseed biomass requires pretreatment to disrupt its recalcitrant structure, thereby enhancing bioenergy yield. Techno-economic assessments have also indicated that the low cost of seed biomass improves its economic viability in the bioenergy sector. Therefore, this chapter explores compositional characteristics and the diverse spectrum of bioenergy derived from oilseed biomass, detailing its pretreatment methods, conversion technologies, and associated bioprocesses. This chapter also offers detailed insights into the environmental and economic aspects through life cycle assessment, along with its potential application in the circular bioeconomy. Furthermore, this chapter highlights the potential of oilseed biomass as a sustainable and renewable alternative energy source that contributes towards improving waste management.