In a study of a sample of 2,705 international plant location decisions by listed Japanese multinational corporations across a possible set of 155 countries in the 1990-1996 period, we use neoinstitutional theory and research on political institutions to explain organizational entry into new geographic markets. We extend neoinstitutional theory's proposition that prior decisions and actions by other organizations provide legitimization and information to a decision marked by uncertainty, showing that this effect holds when the uncertainty comes from a firm's lack of experience in a market but not when the uncertainty derives from the structure of a market's policymaking apparatus.