This paper studies the performance consequences of the speed of SME internationalization. The authors identify three research gaps: few studies treat speed as an independent variable; most studies analyze speed only until internationalization starts; and, finally, studies have paid little attention to the multidimensionality of the speed concept. The authors seek to address these gaps and to contribute to the literature on the dynamics of internationalization by developing three measures of internationalization speed, which capture its multidimensionality. Building on the theories of learning advantage of newness and time compression diseconomies, the study presents three hypotheses on speed’s effect on performance, and the theoretically derived research model is tested on a sample of 183 SMEs visited on site. The analysis demonstrates that the speed of a firm’s increase in the breadth of its international markets has a positive but curvilinear effect on firm performance. It also demonstrates that the speed of a firm’s increase in commitment of foreign resources has a negative but curvilinear effect on the performance of the firm. These results have implications both for scholars interested in the dynamics of firm internationalization and for SME managers.