Preheat and grease a waffle iron according to manufacturer's instructions.
Sift flour, baking powder, and salt together in a bowl. Whisk buttermilk, yogurt, butter, eggs, and sugar together in a separate bowl; stir into flour mixture until batter is smooth. Fold strawberries into batter.
Pour about 1/3 cup batter into preheated waffle iron; cook until lightly browned, 5 to 7 minutes. Repeat with remaining batter.