Preheat the oven to 375°F (190°C) and line a 12-cup muffin tin with paper liners.
In a large mixing bowl, whisk together the flour, sugar, baking powder, and salt.
In a separate medium bowl, whisk the vegetable oil, whole milk, eggs, and vanilla extract until well combined.
Pour the wet ingredients into the dry ingredients and stir with a spatula until just combined, being careful not to overmix.
Gently fold the chia seeds into the batter until evenly distributed.
Divide the batter equally among the 12 muffin cups, filling each about three-quarters full.
Bake for 18 to 22 minutes, or until a toothpick inserted into the center of a muffin comes out clean.
Remove from the oven and allow the muffins to cool in the tin for 5 minutes before transferring to a wire rack.