The global imperative for decarbonization has spurred significant interest in alternative fuels for internal combustion engines. Ammonia emerges as a promising candidate due to its complete combustion producing only nitrogen and water as byproducts. This review investigates the potential of ammonia as a carbon-free fuel for internal combustion engines (ICEs), focusing on the promising dual-fuel combustion strategies. While ammonia offers significant environmental benefits, including reduced greenhouse gas emissions and improved air quality, its implementation faces challenges such as low flame propagation speed, high autoignition temperature, and increased NOx, N2O and unburned ammonia emissions. The review explores current research efforts to address these issues, including the use of combustion promoters and optimized engine parameters. Despite these technical obstacles, ammonia’s potential to contribute to a sustainable future is evident, and ongoing research and development are crucial to unlock its full potential as a clean and efficient fuel for the transportation sector.