Preheat your oven to 350°F (175°C). Line a muffin pan with paper liners and set aside.
In a large bowl, whisk together the flour, baking soda, baking powder, salt, pumpkin pie spice, sugar, and cinnamon.
Add the pumpkin purée, melted butter, eggs, and vanilla. Mix until well combined.
Shred the zucchini using a grater.
Stir the shredded zucchini into the batter until just mixed—don’t overmix.
Fill each muffin cup about ¾ full using a spoon or cookie scoop.
Bake for 20 minutes, or until a toothpick inserted in the center comes out clean.
Let the muffins cool before serving.