This study has examined the e ect of public investment on private invest-rnment in Ethiopia during 1993 to 2018. It also examined their relative con-rntribution to economic growth. The study employed the ARDL bounds testingrnapproach which is initiated by Pesaran & and Shin (1999) and later popularizedrnby (Pesaran, et al., 2001). The empirical results reveal that public investmentrnhas a crowding-in e ect on private investment in the long run which means,rnpublic investment stimulates private investment in the long run. In the shortrnrun, however, public investment has a crowding-out e ect on private investment.rnThe previous year public investment also declines the current period private in-rnvestment in the short run. On the other case, public investment has no directrnimpact on economic growth in the long run. Economic growth is positively as-rnsociated with private investment although it is statistically insigni cant in thernlong run. However, it has no any immediate e ect on private investment in thernshort run. On the other direction, private investment has a signi cant positivernimpact on economic growth in the long run while it is negatively related torneconomic growth in the short run. This suggests that there is a unidirectionalrne ect, which means private investment could a ect economic growth while itrnis not vice versa. In addition, private investment positively contributes to eco-rnnomic growth more than public investment. Real interest rate has a signi cantrnnegative e ect on private investment in the long run while it is positively asso-rnciated with private investment in the short run. However, real interest rate hasrnno direct signi cant impact on economic growth in the long run.