Cook the pasta in a large pot of salted boiling water according to package instructions until al dente, about 8-10 minutes. Drain and rinse under cold water.

In a large mixing bowl, combine the cooled pasta, sliced pepperoni, diced mozzarella, halved cherry tomatoes, sliced black olives, diced green bell pepper, and finely chopped red onion. Toss gently to mix.

Drizzle the Italian dressing over the salad and toss again until all ingredients are evenly coated.

Season with dried oregano, salt, and pepper to taste, folding gently to mix without bruising the vegetables.

Cover the salad and refrigerate for at least 1 hour to let the flavors meld.

Before serving, toss the salad again and adjust seasoning if necessary. Serve chilled.