Preheat the oven to 350°F (175°C).
Prepare a loaf pan by greasing it or lining it with parchment paper.
In a large mixing bowl, combine the grated zucchini, eggs, vegetable oil, and vanilla extract.
In another bowl, whisk together the all-purpose flour, cocoa powder, granulated sugar, brown sugar, baking soda, baking powder, and salt.
Gradually add the dry mixture to the wet ingredients, stirring until just combined.
Fold in the chocolate chips.
Pour the batter into the prepared loaf pan, smoothing the top.
Bake for 50-60 minutes, or until a toothpick inserted into the center comes out clean.
Let the bread cool in the pan for about 10 minutes before transferring to a wire rack.
Slice and enjoy your delicious Double Chocolate Zucchini Bread!