Purpose Marketing managers have strategic choices when forming brand alliances. One such choice is integration, defined as the extent to which the offering is a fusion in the form and function of the partner brands. The paper aims to investigate how integration affects consumer attribution of responsibility to brand alliance partners. Design/methodology/approach This paper builds on the previous study on brand alliances and attribution theory. Multiple experiments are used to test three hypotheses. Findings This research shows that consumers are sensitive to the level of alliance integration, which, in turn, affects attributions of responsibility for the joint offering. Consistent with attribution theory, results show that responsibility for each brand varies systematically by integration and lead brand status vis-a-vis the alliance: while consumers perceive both brands as equally responsible for higher integration brand alliances, responsibility attributions diverge in lower integration alliances based on whether the brand is the alliance host. This pattern also holds for product-harm events. Originality/value This paper explores brand alliances via the level of integration and leads brand status, which are key determinants of consumer attributions of responsibility.