Thousands of millions of tons of municipal solid waste (MSW) are produced every year. Waste management and utilization strategies are major concern in many countries. Incineration is a common technique for treating waste, as it can reduce waste mass by 70% and volume by up to 90%, as well as providing recovery of energy from waste to generate electricity. Generally, municipal solid waste incineration (MSWI) produces two main types of ash, which can be grouped as bottom ashes (BA) and fly ashes (FA). In this review, the utilization methods of MSWI ashes will be studied.