Preheat your oven to 350°F (175°C) and line a muffin tin with paper liners.
In a bowl, whisk together the flour, baking powder, baking soda, and salt.
In a separate bowl, mix the oil and sugar until well combined.
Add eggs one at a time, mixing well after each addition.
Stir in the buttermilk, lemon juice, and lemon zest.
Gradually add the dry ingredients to the wet mixture, stirring until just combined.
Fold in the poppy seeds gently.
Fill each muffin cup about ⅔ full with batter.
Bake for 18-20 minutes or until a toothpick comes out clean.
Remove from oven and cool for a few minutes before transferring to a wire rack.