Gather all ingredients and prepare your vegetables.
In a small bowl, whisk together olive oil, red wine vinegar, Dijon mustard, oregano, garlic, salt, and black pepper until well combined.
Set the vinaigrette aside.
Bring a large pot of salted water to a boil and cook the bowtie pasta according to package directions until al dente.
Drain the pasta and rinse briefly with cool water to stop the cooking process. Drain well.
While the pasta cools, chop the tomatoes, zucchini, yellow squash, broccoli, parsley, roasted red peppers, and red onion.
Add the cooled pasta and all vegetables to a large mixing bowl.
Whisk the dressing once more and pour it over the salad.
Toss until the Summer Vegetable Pasta Salad is evenly coated.
Taste and adjust seasoning with additional salt and pepper if needed.
Serve immediately or refrigerate for at least 30 minutes before serving for even better flavor.