Preheat your oven to 350°F (175°C). Grease a muffin tin or line with paper liners.
In a large mixing bowl, combine the grated zucchini, sugar, oil, and vanilla extract. Mix well.
In another bowl, whisk together the flour, baking powder, baking soda, salt, and cinnamon.
Gradually add the dry ingredients to the wet ingredients, stirring until just combined. Do not overmix.
Divide the batter evenly among the muffin cups.
Bake for 20-25 minutes, or until a toothpick inserted into the center comes out clean.
Allow the muffins to cool in the tin for 5 minutes, then transfer to a wire rack to cool completely.