Biodiesel, a sustainable and environmentally friendly alternative to petroleum diesel, is derived from vegetable oils or animal fats. It has gained significant attention in recent years due to its potential to reduce greenhouse gas (GHG) emissions and reliance on fossil fuels. This chapter explores various aspects of biodiesel production, including feedstocks, technologies, fuel properties, limitations, and future directions for its development. Biodiesel is produced through transesterification, a process that combines animal or plant fats with methanol or ethanol to produce methyl or ethyl esters. These esters exhibit properties similar to conventional diesel, allowing their use in compression-ignition engines with minimal or no modifications. Biodiesel offers several advantages over traditional diesel, including reduced particulate matter, sulfur, and carbon monoxide (CO) emissions. Additionally, it enhances energy security by utilizing domestic feedstocks, thereby decreasing dependence on imported oil. Biodiesel can be used independently or blended with petroleum diesel, offering a cleaner alternative with lower emissions. Despite these benefits, biodiesel production faces challenges, particularly in feedstock flexibility and cost-effectiveness. Traditional transesterification remains the predominant method of production, but emerging technologies such as supercritical fluid transesterification, enzymatic transesterification, and algal biodiesel are gaining prominence due to their potential for improving sustainability and efficiency. Continued research and innovation are essential to overcome these challenges and to develop more efficient and cost-effective biodiesel technologies in the future.