In a mixing bowl, combine the peanut butter and Greek yogurt. Stir until smooth and well combined.
Add the honey (or maple syrup), vanilla extract, and cinnamon. Mix thoroughly.
If the dip is too thick, gradually add milk, one tablespoon at a time, until it reaches your desired consistency.
Taste and adjust sweetness if needed.
Serve immediately with fresh fruit, or store in an airtight container in the refrigerator for up to 3 days.