A legal rhino horn trade is suggested in order to reduce poaching. To examine the implications of this proposition, we conducted a choice experiment with 345 rhino horn consumers in Vietnam, investigating their preferences for legality, source, price and peer experience of medicinal efficacy as attributes in their decision to purchase rhino horn. We calculated consumers' willingness to pay for each attribute level. Consumers preferred and were willing to pay more for wild than semi-wild and farmed rhino horn but showed the strongest preference for legal horn, although higher-income consumers were less concerned about legality. The number of peers having used rhino horn without positive effect reduced preference for wild-sourced horn and increased preference for legality. Our results suggest that a legal trade in rhino horn would likely continue to face competition from a parallel black market. Whether poaching would be reduced depends on the legal supply of wild and semi-wild horns, campaigns ability to change consumer preferences, and regulation efforts.