Preheat the oven to 350°F (175°C) and grease or line a 9x5-inch loaf pan with parchment paper.
Prepare the zucchini by grating it and squeezing out excess moisture with a clean kitchen towel or paper towels.
In a medium mixing bowl, whisk together the flour, baking powder, baking soda, salt, and lemon zest.
In a large mixing bowl, combine the sugar, vegetable oil, eggs, lemon juice, and vanilla extract. Whisk until fully incorporated. Add the grated zucchini to the wet ingredients and mix gently.
Gradually fold the dry ingredients into the wet mixture, stirring until just combined. Be careful not to overmix.
Pour the batter into the prepared loaf pan and smooth the top with a spatula.
Bake for 55–60 minutes, or until a toothpick inserted into the center comes out clean.
Let the bread cool in the pan for 10 minutes, then transfer it to a cooling rack to cool completely before slicing.