The competitive nature of knowledge transfer and the process of organizational learning between partners constitute a fundamental challenge for both academics and practitioners alike. By focusing on one type of competency - marketing know-how - this research examines the role of knowledge ambiguity pertaining to the process of knowledge transfer in international strategic alliances. Based on a cross-sectional sample of 151 multinationals and a structural equation methodology, this study empirically investigates the antecedents of knowledge ambiguity: tacitness, asset specificity, complexity, experience, partner protectiveness, cultural distance, and organizational distance. Further, the strength of the relationships between these theoretical constructs and ambiguity is examined in light of the possible moderating effects of collaborative experience, firm size, and the duration of the alliance entered. Consistently, tacitness emerges as the most significant determinant of knowledge transferability. Moreover, the effects of cultural distance, asset specificity, and prior experience are moderated respectively by the firm’s level of collaborative experience, the duration of the alliance, and the firm’s size. © 1999, Academy of International Business. All rights reserved.