The arts and cultural sector offers a beneficial field of cross-sector collaboration for businesses as it is closely related to contemporary consumers’ lifestyle and civilization. This study examined the impact of two prominent cross-sector collaborations (i.e. partnership and sponsorship) on corporate reputation in the arts and culture sector, with the focus on a specific stakeholder group—the millennials. 154 millennials were recruited for an online experiment, using a convenience sampling through posting an open-call on the Facebook pages of the 100 most visited art museums in the world. The results show that partnership and sponsorship both indicate a positive effect on corporate reputation, whereas partnership is more appealing to the millennials than sponsorship. We also examined the moderation effects of sincerity, value alignment and credibility on the relationship of cross-sector collaboration and corporate reputation. All three moderators are found to strengthen the relationship, while the impact of credibility is the strongest among them. The findings imply that companies should be aware of the need to present themselves as a trustworthy collaborator and the necessity to fulfil their duties deriving from the engagement in a particular cross-sector collaboration.