Legislation, in the form of presumed consent, has been argued to boost organ donation but most evidence disregards the practice of seeking relative’s consent, which can either ‘veto’ donation decisions, or ‘legitimize them’, by removing any possible conflict with the donor’s family. We study the effect of presumed consent alongside family consent on individuals’ willingness to donate (WTD) one’s own and relatives’ organs, and on actual organ donation behaviours. Using data from 28 European countries for the period 2002–2010, we found that presumed consent (PC) policies are associated with increased willingness to donate organs, but this effect was attenuated once internal family discussions on organ donation were controlled for. Our findings indicate that relative’s consent acts as a veto of donation intentions and attenuates the effect of regulation on actual donations. More specifically, PC increases WTD one’s own and relatives’ organs in countries where no family consent is required. Consistently, we find that family consent attenuates the influence of regulatory environment on actual donations. The effect is driven by the influence of family discussions which increased WTD, and in combination with presumed consent translated into higher organ donation rates.