Lay a tortilla flat on a clean surface.
Spread a small amount of pizza sauce evenly over the tortilla.
Place one mozzarella stick at one end of the tortilla.
Add three slices of pepperoni on top of the cheese.
Starting at the end with the cheese, roll the tortilla tightly into a stick shape.
Repeat with the remaining tortillas.
If desired, lightly brush the outside of each pizza stick with melted butter for extra crispiness.