Preheat the oven to 350°F (175°C) and line a muffin tin with paper liners.
In a large mixing bowl, combine the flour, cocoa powder, sugar, baking powder, baking soda, and salt.
In another bowl, whisk together the milk, vegetable oil, and eggs until combined.
Pour the wet ingredients into the dry ingredients and gently mix until just combined.
Fold in the chocolate chips gently into the batter.
Spoon the batter into the prepared muffin tin, filling each liner about 2/3 full.
Bake in the preheated oven for 18-20 minutes, or until a toothpick inserted comes out clean.
Remove from the oven and let cool in the pan for 5 minutes before transferring to a wire rack.