Preheat oven to 375 degrees F (190 degrees C). Grease muffin cups or line with paper muffin liners.
In a large bowl, stir together the flour, oats, baking powder, baking soda, salt, and cinnamon.
In a separate bowl, cream together the butter and sugar until light and fluffy. Beat in the eggs one at a time, then stir in the vanilla. Add the flour mixture alternately with the milk; stir just until blended.
Gently fold in the chopped strawberries, and spoon the batter into the prepared muffin cups.
Bake for 18 to 20 minutes in the preheated oven, until the tops are golden brown and a toothpick inserted into the center of a muffin comes out clean.