The diffusion of modern, efficient technology has far-reaching consequences for the geography of economic activity, inequality, and environmental quality. This article examines two popular yet highly controversial claims about the conditions most favorable to the rapid spread of new technology. The first states that latecomer advantage allows developing countries to diffuse new technology faster than developed countries. The second claim, widely articulated by advocates of neoliberal policy reform, is that new technologies diffuse more rapidly where countries are “open” to international trade and investment. To investigate these claims we use event-history analysis to estimate the determinants of diffusion speed across a large panel of developed and developing countries for three very different technologies. These are: continuous steel casting, shuttleless textile weaving looms, and digital telephone mainlines. Our results broadly support both propositions. Countries that adopt new technology later or have a smaller existing capital stock—characteristic features of developing countries—diffuse new technology more rapidly than countries that adopt earlier or have more installed capacity—two characteristics of developed countries. Trade openness is also found to influence the rate of diffusion positively for all three technologies. Yet, consistent with recent empirical studies, we fail to find support for the idea that foreign direct investment (FDI) accelerates the diffusion of new technology in host economies. The article concludes by discussing the geographical implications of our findings.