Preheat your oven to 350°F (175°C). Grease a loaf pan.
In a large bowl, mix together the grated zucchini, mashed bananas, vegetable oil, sugar, beaten eggs, and vanilla extract.
In another bowl, whisk together the flour, baking soda, salt, and ground cinnamon.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
Pour the batter into the prepared loaf pan.
Bake for about 60 minutes, or until a toothpick inserted into the center comes out clean.
Let the bread cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.