In a large bowl, combine the spinach, artichoke hearts, cream cheese, sour cream, mayonnaise, mozzarella cheese, Parmesan cheese, garlic, salt, and pepper.
Mix until well combined.
Transfer the mixture to a crockpot.
Cover and cook on low for 2-3 hours, or until heated through and bubbly.
Stir well before serving.
Serve warm with gluten-free crackers or vegetables.
Notes
Make sure to thoroughly drain the spinach to avoid a watery dip.
This dip can be made ahead of time and reheated in the crockpot.