Cook the spaghetti according to package instructions until al dente. Drain and rinse with cold water to cool.

While the pasta is cooking, chop all the vegetables into bite-sized pieces.

In a large bowl, combine the cooked spaghetti, chopped vegetables, and olives.

Pour the Italian dressing over the salad and toss until everything is well coated.

Add the grated Parmesan cheese (if using) and season with salt and pepper to taste.

Chill in the refrigerator for at least 1 hour before serving to let the flavors meld.

Garnish with chopped parsley before serving, if desired.