Heat olive oil in a large pot over medium heat. Add beef and brown on all sides. Remove beef from pot and set aside.
Add onion, carrots, and celery to the pot and cook until softened, about 5-7 minutes.
Return beef to the pot. Add beef broth, barley, thyme, and bay leaf. Bring to a boil, then reduce heat and simmer for 90-120 minutes, or until barley is tender.
Remove bay leaf before serving. Season with salt and pepper to taste.