Warm the olive oil in a large pot over medium heat. Add the onion, carrots, and celery and cook for 5 minutes, stirring, until the onion begins to soften.
Stir in the garlic and cook for 30 seconds, until fragrant.
Add the tomatoes, vegetable broth, zucchini, green beans, Italian seasoning, salt, and pepper. Bring to a boil.
Reduce the heat to medium-low, cover, and simmer for 15 minutes, until the carrots and zucchini are fork-tender.
Taste and adjust the seasoning. Ladle the soup into bowls and serve hot.