In a large bowl, combine the eggplant, zucchini, bell pepper, red onion, cherry tomatoes, and garlic. Drizzle with olive oil and sprinkle with Greek seasoning, salt, and black pepper.
Spread the mixed vegetables in a single layer on a baking sheet to allow even roasting.
Roast in the preheated oven for 35 to 40 minutes. Stir or flip the vegetables halfway through. Remove from the oven and garnish with chopped fresh parsley, if desired. Serve warm.