In a large bowl, combine the cubed eggplant, zucchini, yellow squash, red bell peppers, onion, and minced garlic.
In a separate bowl, whisk together the diced tomatoes with juice, tomato paste, chopped basil, thyme, olive oil, salt, and pepper.
Pour the tomato mixture over the vegetables and gently stir to coat evenly.
Transfer the vegetable mixture to a 6-quart slow cooker.
Cover the slow cooker and cook on low for 4 hours, or until the vegetables are tender and the flavors have blended together.
Gently stir the ratatouille to combine the vegetables and sauce.
