Preheat the oven to 375 degrees and line a muffin tin with paper liners. Combine gluten free flour, gluten free oats, brown sugar, baking powder, baking soda, and salt in a large bowl. Stir to combine.
In a separate bowl, mash bananas with a fork.
Add eggs, oil, and milk and whisk until combined.
Add the wet ingredients to the dry ingredients and stir until just combined.
Add chocolate chips and mix until evenly distributed.
Fill each muffin cup halfway full of batter and bake in preheated oven for 18 to 20 minutes, or until a toothpick inserted in the middle comes out clean.