Place the beef stew meat in the bottom of the slow cooker.
Add the chopped onion, sliced carrots, cubed potatoes, and minced garlic on top of the meat.
Sprinkle the pearl barley, dried thyme, salt, and black pepper over the vegetables.
Pour the beef broth into the slow cooker and tuck the bay leaves into the liquid.
Cover and cook on low for 8 hours until the beef is tender and the barley is soft.
Remove the bay leaves before serving.