Does official aid pave the road for private foreign investment or does it suffocate private initiative by diverting resources towards unproductive activities? We explore this question using panel data covering a large number of developing and emerging economies during the 1990s. Controlling for countries’ institutional environment, we find that, evaluated at the mean, the marginal effect of aid on private foreign investment is close to zero. Surprisingly, however, the effect is strictly positive for countries in which private agents face a substantial regulatory burden. This result is robust across a wide range of specifications, samples and estimation methods.