This paper aims at understanding the role of technological and behavioral uncertainties in shaping alliance partners’ strategies in the post-alliance formation stage.  While high technological uncertainty is likely to foster cooperation, high behavioral uncertainty is expected to encourage competition.  Identifying the joint impact of these uncertainties on partners’ strategies helps us gain fruitful insights regarding the partners’ behavior in the post-alliance formation stage in a much fine-grained fashion. Thus, this paper enriches the debate regarding the interplay of competition and cooperation by showing that high levels of cooperation do not necessarily lead to a reduction of competition, and vice versa.