Three theoretical perspectives summarize diversification antecedents and performance outcomes. The first perspective examines diversification under the assumption of relative market perfection where, within industries, firms and products are homogeneous. The second perspective discusses diversification where both market and firm imperfections are assumed to exist. The thirdperspective also assumes market andfirm imperfections, butfurther assumes imperfect governance structures such that managerial motivesfor diversification are influential. These perspectives provide different explanations of antecedent resources and incentives that encourage (or discourage) diversification. This article reviews evidence associated with each perspective concerning the relationship between diversification and firm performance and offers suggestions forfuture research based on comparisons among these alternative perspectives. © 1990, Sage Publications. All rights reserved.