Preheat oven to 350 degrees F (175 degrees C). Grease 12 muffin cups or line with paper muffin liners.
Whisk together spelt flour, oats, baking soda, and cinnamon in a bowl. Stir together bananas, oil, and sugar in a separate bowl. Stir banana mixture into spelt mixture just until dry ingredients are moistened; divide mixture evenly into 12 muffin cups.
Bake in the preheated oven until a toothpick inserted into the center comes out clean, about 18 minutes. Cool in pan for 10 minutes; remove to cool completely on a wire rack.
