Place bacon in a large, deep skillet. Cook over medium heat for 10 to 15 minutes, or until crisp. Drain, crumble, and set aside.
Warm tortillas in microwave oven for 30 to 45 seconds, or until soft. Spread 1 tablespoon Ranch dressing down the center of each tortilla. Layer crumbled bacon, avocado, tomato and lettuce over the dressing. Roll the tortilla around the other ingredients.