Preheat oven to 375°F and line a muffin tin with paper liners.
In a large bowl, whisk together flour, granulated sugar, brown sugar, baking powder, baking soda, and salt.
In another bowl, mix melted butter, eggs, orange juice, orange zest, milk, and vanilla until smooth.
Pour the wet mixture into the dry ingredients and stir until just combined. Do not overmix.
Divide batter evenly among the muffin cups, filling each about two-thirds full.
Bake for 18 to 20 minutes, or until a toothpick inserted comes out clean.
Cool muffins in the pan for 5 minutes, then transfer to a wire rack to finish cooling.