In three institutional environments, this study examines the uncertainty-reducing effects of experiential knowledge of varying specificity in the market entry process. The goal of the study is to answer the research question: What is the uncertainty-reducing effect of experiential knowledge of varying specificity in markets with different institutional distances from a firm's home base? The authors develop a theoretical model using the most recent developments in internationalization process theory. They test the model with a data set collected on-site at 203 small and medium-sized enterprises with entry experience into the new Eastern European Union member-states, Russia and China. The analysis shows no support for the claim that internationalization knowledge reduces uncertainty in the market entry process. Rather, the analysis reveals that societal knowledge of the entering firm has an uncertainty-reducing effect in markets that are relatively less distant from its home market. The analysis also shows that international experiential knowledge of high specificity, an important type of marketing knowledge, provides the greatest uncertainty-reducing effect.