Recent theorizing has proposed that modular product and process architectures are key enablers of strategic flexibility. We formulated an integrative conceptual model encompassing antecedents, contributing factors, and outcomes of modularity. We then tested this model on data from managers in U.S. and U.K. home appliance companies using structural equations modeling. The results indicate a positive relationship between modular product architectures and performance, with product model variety as a mediating variable. The results also highlight linkages between perceptions of market context and the use of modular products architectures, and between complementary organizational capabilities and firm performance. Copyright © 2002 John Wiley & Sons, Ltd.