Preheat oven to 350°F. Prepare 2-8 inch loaf pans with nonstick cooking spray.
In a large mixing bowl, combine granulated sugar, vegetable oil, eggs, and vanilla extract. Whisk to combine.
Add in all-purpose flour, baking soda, baking powder, salt, and cinnamon, and fold into the wet ingredients with a spatula. The mixture will be very thick.
Add in shredded zucchini and continue to fold the mixture until the zucchini is well dispersed throughout the batter.
Divide the batter into the 2 prepared loaf pans and spread evenly.
Bake for approximately 40-45 minutes until a toothpick comes out clean and the tops of the zucchini breads are fully set.
Remove from the oven and allow the breads to cool in the pan for about 15 minutes. Transfer to a wire rack to cool completely.