Lightly butter one side of each flour tortilla. Heat a large skillet to medium-high heat. Place the tortilla into the pan butter side down. Spread a thin layer of pizza sauce on half of a tortilla. Sprinkle a layer of cheese over the pizza sauce. Top with pepperoni and black olives. Cook until the cheese has melted and the bottom has browned.
Fold the tortillas in half and press down the edges gently.
Remove from pan. Repeat until all of the quesadillas are cooked. Slice each quesadilla into three triangles.