Bring a large pot of salted water to a boil. Add the rotini pasta and cook until al dente, about 8-10 minutes. Drain and rinse under cold water.

In a large mixing bowl, add the cooled rotini pasta, sliced pepperoni, diced mozzarella cheese, halved cherry tomatoes, sliced black olives, diced green bell pepper, and finely chopped red onion. Gently mix together.

Pour Italian dressing over the pasta mixture. Toss to coat all ingredients with the dressing.

Sprinkle dried oregano, salt, and pepper to taste over the mixture and fold gently to combine.

Cover with plastic wrap or a lid and refrigerate for at least 1 hour to allow flavors to meld.

After chilling, toss the salad again to redistribute the dressing and check seasoning, adjusting if necessary.

Serve the chilled Pizza Pasta Salad in bowls or a serving dish.