Preheat the oven to 350 degrees and line a 12 count muffin tin with cupcake liners.
Combine the flour, sugar, baking powder, baking soda in a large bowl. Stir in the cinnamon, milk, oil, egg, pumpkin, and zucchini until fully incorporated.
Fill each muffin well about 3/4 full. Bake for 20-25 minutes.
Around 20 minutes insert a toothpick into the muffins and if it comes out clean, they are done.