Butter is gluten-free. While some cheeses can have additives or flavorings that contain gluten, butter is usually a low risk unless flavored. However, always be sure to read the label to see if a particular brand is gluten-free.
Also, be wary of cross-contact when it comes to butter in the fridge (think shared knives and “double-dipping” when spreading onto bread.)
For information on Peanut Butter, click here.