This study examined the determinants of tax revenue mobilization with evidence from Ethiopia using time serious data from 1987 to 2017. The tax effort function is used by regressing tax revenue on real gross domestic product, openness, exchange rate, inflation rate, rate of external debt to GDP, share of agriculture to GDP, share of industry to GDP and share of service sector to GDP. Results from the analysis showed that Real GDP and external debt, is vital in generating tax revenue in the long run but insignificant effect in short run. It implied that Real GDP and external debt is a good policy instrument in raising tax revenue in the long run. Trade openness has a positive and significant effect in long run and short run in generating tax revenue. Furthermore, the study revealed that, exchange rate had a negative impact on tax revenue in long run dynamics were employed. Service sector has negative and significant effect on tax revenue mobilization in short run but insignificant effect in the long run. The study recommended measures that boost Real GDP, trade openness, external debt, structural transformations, and introduction of new tax bases have to be considered so as to bring efficient in enhance tax revenue.