Preheat oven to 350 degrees F (175 degrees C). Grease and flour 24 muffin cups.
In a large bowl, combine cake mix, oil, eggs, yogurt and vanilla. Beat with an electric mixer on low speed for 30 seconds, then on medium for 2 minutes.
Spoon batter into prepared muffin cups. Bake for 18 to 20 minutes in the preheated oven, or until a toothpick inserted into the center of a cupcake comes out clean.
Cool in pan for 10 minutes before removing to cool completely on a wire rack.