In general, pizza sauce does not contain gluten-containing ingredients. However, if the pizza isn't labeled gluten-free, then it's hard to say for sure. Mainly because of cross-contamination or preservatives and additives the brand is using. Some store-bought gluten-free pizza sauces are available, but these options are pricey.  Rao's pizza sauce is my favorite store-bought gluten-free pizza sauce, and it's also low carb, keto, and Whole30 compliant. The only issue is it costs between $4.50 - $5 for a 13-ounce jar.  Yes, it's possible to purchase gluten-free sauce from the store. However, it's more cost-efficient to prepare homemade gluten-free pizza sauce. If you want to use all organic ingredients or a particular tomato sauce brand, cooking homemade allows you to control.