Heat the olive oil in a large, deep pot over medium-high heat.
Add the beef stew meat and chopped onion to the pot. Sauté until the beef is browned on all sides and the onions begin to soften, about 5–7 minutes.
Stir in the minced garlic and cook for another 30 seconds until fragrant.
Add the sliced carrots, chopped bell pepper, diced tomatoes, beef broth, pearl barley, Worcestershire sauce, thyme, red wine, and the brown gravy mix. Stir to combine.
Season with salt and pepper to taste, then bring the mixture to a boil.
Reduce the heat to low, cover, and let simmer for 50–60 minutes, or until the beef is tender and the barley is fully cooked. Stir occasionally to prevent sticking.
Taste and adjust seasoning as needed.
Serve hot, garnished with freshly chopped parsley if desired.
Enjoy!