Place a Dutch oven over medium heat. Add the ground beef and cook until browned, breaking it apart with a spoon. Drain any excess fat.
Stir in the onion and garlic. Cook for 3 minutes until the onion softens.
Add the carrots, green beans, potatoes, beef broth, diced tomatoes, thyme, salt, and pepper. Stir to combine.
Bring the mixture to a boil, then reduce the heat to low. Cover and simmer for 35 minutes, stirring once or twice, until the vegetables are tender.