Preheat the oven to 350 degrees F (175 degrees C). Line a 12-cup cupcake pan with paper liners.
Whisk vegetable oil, egg, milk, lemon juice, and vanilla extract together in a bowl.
Combine flour, sugar, chocolate chips, baking soda, cinnamon, and salt in a separate bowl. Pour in oil mixture and fold gently to combine. Stir in zucchini. Spoon batter into the prepared pan.
Bake in the preheated oven until a toothpick inserted into the center comes out clean, about 20 minutes. Transfer to a wire rack to cool.