In this paper, we build indexes that measure the average geographic concentration of a country's imports and of its suppliers' imports. We show these indexes correlate with various measures of economic vulnerability. The geographic concentration of imports varies a lot across countries. The imports of small, poor and closed countries are unambiguously much less diversified from a geographic point of view than those of big, rich and open economies. The geographic diversification of suppliers' imports exhibits less cross-country variation, and once the geographic concentration of a country's own imports is considered, country characteristics are only modestly related to the geographic concentration of its suppliers' imports. The high geographic concentration of small, poor and closed countries' imports is partly, but not entirely, explained by the gravity of trade flows.