Alcohol fuels have been increasingly considered for internal combustion (IC) engines due to their potential to address rising energy costs and reduce greenhouse gas emissions. Ethanol and methanol are the primary alcohol fuels studied for this purpose. Ethanol is valued for its higher-octane number, which allows for increased compression ratios and improved thermal efficiency in IC engines. Its oxygen content promotes more complete combustion, thereby reducing emissions of carbon monoxide and unburned hydrocarbons. On the other hand, methanol is noted for its high-octane rating and potential for use in various engine types. Both ethanol and methanol are produced from renewable sources, supporting their role as sustainable alternatives to traditional fossil fuels. The combustion properties of alcohol fuels, such as their lower energy density and higher viscosity compared to gasoline and diesel, are also examined. Challenges related to the use of alcohol fuels include their impact on engine performance and fuel system materials. Ongoing research aims to address these challenges and enhance the viability of alcohol fuels in IC engines, contributing to a cleaner and more sustainable energy future.