Preheat oven to 350° F. Prepare a 13 x 18 baking sheet with nonstick spray or parchment paper.
In a large bowl, gently whisk white whole wheat flour, pumpkin spice, baking powder, baking soda, and salt. Add chocolate chips and toss to evenly coat.
In a separate large bowl, whisk pumpkin, buttermilk, sugar, oil, eggs, and vanilla until combined.
Add liquid ingredients to flour mixture. Using a spatula, fold ingredients just until moistened. Do not over mix.
Pour batter onto prepared baking sheet and spread evenly with a spatula. Bake 30 minutes or until slightly golden and a toothpick inserted into the middle comes out clean. Cut into bars. Enjoy!