Sometimes — with care
Unlike for dogs and cats, grapes are not kidney-toxic to rabbits — but they ARE sugar bombs. One grape occasionally is fine; a bunch is a gut-health incident.
The grape/raisin kidney mystery applies to dogs (and likely cats), not rabbits: rabbits digest grapes without that specific risk, and a grape is a classic high-value rabbit treat. The constraint is the same as all rabbit fruit: sugar disrupts the cecal flora that rabbit health utterly depends on, and grapes are among the sugariest fruits (~16%). Raisins are worse — concentrated to ~60% sugar — so treat raisins as “a single one, rarely”.
One grape, once or twice a week, within the overall fruit budget. Cut it in half for small breeds. Raisins: one, rarely. None for juveniles, overweight rabbits or sensitive guts. Always alongside unlimited hay.
Rotate single-grape weeks with apple slivers or fresh herbs like basil and mint.
This article is general information, not veterinary advice. If your pet has eaten something potentially harmful or shows symptoms, contact your vet or an emergency clinic immediately. Full disclaimer.