Preheat your oven to 350°F (175°C). Grease a loaf pan.
In a large mixing bowl, combine the flour, sugar, baking soda, baking powder, cinnamon, and salt.
In another bowl, mix the vegetable oil, crushed pineapple, grated zucchini, and vanilla extract.
Add the wet ingredients to the dry ingredients and stir 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.