Preheat the oven to 325 degrees F (165 degrees C). Grease and flour four 12-cup muffin tins or line cups with paper liners.

Whisk flour, sugar, baking powder, baking soda, cinnamon, and salt together in a large bowl; make a well in the center. Pour oil and eggs into the well: stir in zucchini, pineapple, and vanilla extract until batter is smooth.

Divide batter among the prepared muffin cups, filling each 2/3 to 3/4 full.

Bake in the preheated oven until a toothpick inserted into centers comes out clean, 20 to 25 minutes.