Preheat the oven to 350 degrees F. Line a baking sheet with parchment paper.
In a bowl, beat together the butter, granulated sugar, and brown sugar until well combined.
Add the mashed banana, egg, and vanilla extract, and beat until well combined.
Add the flours, baking soda, and salt, and stir until well combined.
Mix in the oats, followed by the chocolate chips.
Form the dough into tablespoon-sized dough balls and place on prepared baking sheet, spacing them about 2 inches apart.
Bake in the preheated oven for 9-11 minutes, until the edges are slightly golden.
Cool on baking sheet for 5 minutes, then transfer to cooling rack.
Enjoy!