Preheat the oven to 350 degrees F. and grease 2, 12-cup muffin tins well.

In a medium bowl, mix pumpkin puree, sugar, eggs, and vanilla until well combined.

Add the whole wheat flour, baking powder, salt, and cinnamon to the wet ingredients and stir until just combined.

Fold in the chocolate chips.

Divide the batter evenly into the prepared muffin tins, filling each about 3/4 full.

Bake for 20 minutes or until the muffins spring back when lightly touched.

Allow the muffins to cool in the tin for 5 minutes, then transfer to a wire rack to cool completely.

Serve warm or at room temperature.