Yes, as long as your hamster is comfortable wearing one. Dr. Jennifer Bruns, DVM, MPVM, with PetSmart Veterinary Services advises that a costume should never be too tight or restrict movement, and should not cover the eyes, mouth, ears or nose. Small pets should never be left alone in a costume. PetSmart's
small pet costumes are built around those guidelines, slip on and off easily and fit most small animals.