Because of the growing demand for energy supplies and growing worries about greenhouse gas emissions, biofuels have attracted a lot of attention. Biofuels can supply liquid fuels, which are necessary for transportation, unlike other green energy sources. With an emphasis on their types and generations, this chapter details current developments in biofuels. Based on the type of feedstock utilized, biofuels are often divided into four generations. Since first-generation biofuels compete with the world’s food demands, their use of edible biomass has generated criticism. Non-edible biomass is used in second generation biofuels; nevertheless, there are still certain restrictions on how cost-effective it is to scale up production to a commercial level. Microbes provide the feedstock for third-generation biofuels, but fourth-generation biofuels concentrate on genetically altering these microbes to produce preferred hydrogen to carbon (HC) yield and constructing an artificial carbon sink to reduce or eliminate carbon emissions. The chapter provides an overview of the four biofuel generations as well as the latest development efforts in this field.