In this article, we examine the effects of three openness measures on 54 industrial and emerging economies' output growth over the "globalization years" of 1986-2004. Controlling for standard determinants of the Solow growth model in panel data, we find positive effects of openness on real output growth. While we find support for higher convergence rates under the open economy, the convergence rates in this article for both samples are remarkably close to the 2% level documented in Mankiw et al. (1992). The inclusion of G/Y, however, reduces the speed of convergence more substantially in industrial economies.