In a large pot, brown the ground beef over medium heat until fully cooked.
Drain excess fat and set the beef aside.
In the same pot, add chopped onion and sauté until translucent.
Stir in minced garlic and cook for an additional minute.
Add diced carrots and celery, cooking until softened.
Return the ground beef to the pot and mix well.
Pour in chopped tomatoes and beef broth, stirring to combine.
Add kidney beans and oregano, seasoning with salt and pepper.
Bring to a boil, then reduce heat and let simmer for 20 minutes.
Serve hot, garnished with chopped green onions.