Preheat the oven to 425 degrees Fahrenheit. Line a large baking sheet with parchment paper or aluminum foil.
Quarter the zucchini and squash, then slice into 1-inch pieces. Arrange in a single layer on the prepared baking sheet. Drizzle the olive oil over and toss to evenly coat.
Sprinkle evenly with Italian seasoning, salt, and pepper (more or less to your taste).
Roast squash for 12-15 minutes, tossing with a spatula halfway through the cook time to ensure even browning.
Garnish with grated Parmesan, if desired, and serve immediately.
