Preheat the oven to 375 degrees F.
Whisk the yogurt and cream cheese together until no cream cheese lumps remain. Stir in the Parmesan, salt, and garlic powder with a spatula or wooden spoon, then stir in the spinach, chopped artichokes, and mozzarella.
Spread the dip in an oven-safe baking dish. Bake for 20 minutes, until the dip is bubbling at the edges.
Serve warm with crusty bread, tortilla chips, pita chips, or crackers.