The article examines if foreign aid affects government revenue sustainably. It looks at data from 148 countries, including 40 Least Developed Countries, from 1980 to 2013. The results show that the impact of aid on non-resource tax revenue depends on a country's income level. For Least Developed Countries, about half of the aid's impact is felt within two to three years, suggesting that while aid has a positive effect on revenue, it may not be long-lasting.