Preheat your oven to 325 degrees. Place 24 cupcake liners in cupcake pans.
In a large bowl, combine cake mix, water, eggs, oil, pumpkin and cinnamon. Once all ingredients are combined, mix on medium speed for two minutes.
Fill cupcake liners with batter approximately 2/3 of the way full.
Bake for 17-22 minutes or until tops spring back lightly when touched.
Remove from oven and place on wire rack. Allow to cool completely prior to frosting.