The quick answer: Yes, in moderation, barring any allergies.
Benefits of peanuts
This oily legume is not like other nuts— it grows more like a potato underground, likely why cats don’t eat too much of these in the wild. Peanuts in particular add crunch and fat to dishes and are used in many cuisines across cultures. They can be a nutritious snack for people if eaten in moderation, but other than being crunchy and possibly entertaining, they don’t do much for a cat’s diet.
As carnivores, cats don’t need too much of the nutrients that peanuts offer, but they’re not necessarily bad for cats provided you don’t overdo it.
Hazards of peanuts for cats
Carbohydrates really aren’t great for cats, and peanuts have plenty of them. Though there’s some protein and fat, the carbohydrates can cause long-term health problems for your cat if you feed them peanuts regularly. So while the errant piece won’t be poisonous, it’s still not an ideal snack.
Proteins may be present in peanuts, but they aren’t complete proteins with everything a cat needs. Though people can substitute plant proteins for a mostly complete diet, this doesn’t work the same for the meat-obsessed little-big cat in your home.
Fat is also a concern; cats need proper amounts of good fat, but it’s preferred that they get this from animal sources to satiate their carnivorous needs. Cats shouldn’t be eating people foods that are high in fat if they want to stay healthy and happy. Vegetable-derived fats can mess with the stomachs and metabolisms of cats over time, so avoiding them is mostly the best strategy.
Allergies can always occur with unfamiliar foods in cats, so be on the lookout for reactions when they eat new things. Choking on small, hard pieces is always a concern, especially with younger cats. They don’t have the proper mouth shape or tooth setup to be processing nuts or kernels, so beware especially with younger or older cats.