Crude glycerol, a byproduct of biodiesel production, has significant value-added potential. As biodiesel production increases, so does the production of crude glycerol, which is a key co-product. Effective utilization of crude glycerol is essential for the economic viability of biodiesel. This review discusses the composition and quality factors of crude glycerol, as well as its value-added applications. Crude glycerol is primarily used as a feedstock for producing other value-added chemicals and as animal feed. Crude glycerol can be used in animal feed, particularly for non-ruminants such as pigs, laying hens, and broilers. It serves as an energy source and is efficiently metabolized by these animals. However, the use of crude glycerol in animal feed requires careful consideration of impurities, such as methanol and potassium, which can affect feed performance and animal health. The optimal levels of crude glycerol in feed formulations need to be determined to ensure efficiency and safety. Crude glycerol is also used in the production of various chemicals through biological and conventional catalytic conversions. These include 1,3-propanediol, citric acid, polyhydroxyalkanoates (PHAs), butanol, hydrogen, docosahexaenoic acid (DHA)-rich algae, monoglycerides, and lipids. These processes offer promising opportunities for converting crude glycerol into high-value products. In addition to these applications, crude glycerol can be used as a fuel for microbial fuel cells and as a co-substrate in anaerobic digestion processes to enhance methane and hydrogen production. It also has potential in the production of bacterial cellulose and as a carbon source for the synthesis of phytase and butanol. Despite the potential, challenges remain in the large-scale utilization of crude glycerol. Impurities in crude glycerol can affect the efficiency of conversion processes, and further research is needed to optimize these processes for commercial viability. The development of sustainable and efficient methods for utilizing crude glycerol is crucial for the future of biodiesel production and the broader bioeconomy.Crude glycerol, a byproduct of biodiesel production, has significant value-added potential. As biodiesel production increases, so does the production of crude glycerol, which is a key co-product. Effective utilization of crude glycerol is essential for the economic viability of biodiesel. This review discusses the composition and quality factors of crude glycerol, as well as its value-added applications. Crude glycerol is primarily used as a feedstock for producing other value-added chemicals and as animal feed. Crude glycerol can be used in animal feed, particularly for non-ruminants such as pigs, laying hens, and broilers. It serves as an energy source and is efficiently metabolized by these animals. However, the use of crude glycerol in animal feed requires careful consideration of impurities, such as methanol and potassium, which can affect feed performance and animal health. The optimal levels of crude glycerol in feed formulations need to be determined to ensure efficiency and safety. Crude glycerol is also used in the production of various chemicals through biological and conventional catalytic conversions. These include 1,3-propanediol, citric acid, polyhydroxyalkanoates (PHAs), butanol, hydrogen, docosahexaenoic acid (DHA)-rich algae, monoglycerides, and lipids. These processes offer promising opportunities for converting crude glycerol into high-value products. In addition to these applications, crude glycerol can be used as a fuel for microbial fuel cells and as a co-substrate in anaerobic digestion processes to enhance methane and hydrogen production. It also has potential in the production of bacterial cellulose and as a carbon source for the synthesis of phytase and butanol. Despite the potential, challenges remain in the large-scale utilization of crude glycerol. Impurities in crude glycerol can affect the efficiency of conversion processes, and further research is needed to optimize these processes for commercial viability. The development of sustainable and efficient methods for utilizing crude glycerol is crucial for the future of biodiesel production and the broader bioeconomy.