Preheat oven to 450 degrees F. Grease a pizza pan and spread the dough onto it.
Spread the ranch dressing over the pizza dough, then scatter the onions over top. Sprinkle with garlic and oregano, then top with the tomatoes. Scatter the crumbled bacon evenly over the pizza followed by the mozzarella and Parmesan cheese.
Bake in the preheated oven until the crust and cheese is golden brown, 12 to 15 minutes. Let the pizza stand for 5 minutes before slicing.