Preheat oven to 400 degrees.
Prepare vegetables but slicing zucchini and yellow squash into half circles, and cutting the onion and peppers into large, bite-sized chunks. Halve the cherry tomatoes.
Place vegetables onto a baking dish and drizzle with 1 1/2 tablespoons of olive oil; toss to evenly coat.
Roast in oven for 25 minutes. Remove and stir, adding in garlic. Return to oven and continue roasting another 5-10 minutes until vegetables reach desired doneness.
Toss with salt, pepper, and fresh basil before serving.