Extant research indicates that the performance effect of international diversification is debatable, and to a great extent is contingent upon a number of firm- and country-specific characteristics. We argue that a critical factor determining the behaviour of the above relationship is the event of acquisition, and more specifically the conditions under which the acquisition takes place. Drawing on resource dependence theory, this paper examines the relationship between international diversification and performance (of target firms) in the post-acquisition period. We suggest that this relationship is contingent upon the size of acquisition (volume of shares acquired), and on whether the target firm has an affiliation to a business group. Utilizing a newly-created dataset comprising 164 publicly listed Indian firms for the period 2001–2015, we find support for our hypotheses.