Onion rings can be vegan, but it depends on the batter.
Batter often contains eggs or milk products.
If you go out to a restaurant, it is not safe to assume that their onion rings are vegan.
Based on what I’ve seen, it’s about a 50/50 chance.
For Example, Harvey’s in Canada Has Vegan Onion Rings
The ingredients in Harvey’s onion rings are:
Onions, water, enriched bleached wheat flour, yellow corn flour, salt, sugar, defatted soyflour, leavening, dextrose, spice extractive, polysorbate 60: blanched in vegetable oil (soybean and/or canola)
There’s a chance that the sugar is not vegan, but it likely is in this case. All the other ingredients are clearly vegan.
They are also cooked in canola oil.
But Burger King Onion Rings Are NOT Vegan
On the other side, onion rings at many fast food restaurants have multiple non-vegan ingredients.
Here is a snippet of the ingredient list for BK onion rings:
Contains 2% Or Less Of :…Natural Flavors, Grill Flavor (From Sunflower Oil), Canola Oil, Wheat Gluten, Modified Palm Oil, Sodium Tripolyphosphate, Whey…
Whey is derived from milk and is never vegan.
You’ll need to look up the ingredients of the onion rings for the restaurant that you’re interested in, or contact them if that information isn’t easily available.
It’s a pain, but this isn’t a food that you can safely assume is vegan.