In a sealable bag, add beef, flour, salt, and pepper. Toss to evenly coat beef in the four.
Place a skillet with olive oil over medium heat and add the beef in a single layer. Brown on all sides and move to slow cooker. You may need to do this in batches so the pan is not crowded.
Add thyme, carrots, onions, celery, barley, wine, and broth to the beef in the slow cooker. Gently stir.