Place lentils in a small pot and cover with 2 cups hot water. Bring to a boil; reduce heat and simmer until lentils are tender, about 15 minutes. Drain.
Heat a large nonstick skillet over medium heat. Add onions; cook and stir until softened, 3 to 5 minutes. Add ground beef and green bell pepper; cook and stir until browned, about 8 minutes.
Stir drained lentils, ketchup, barbeque sauce, Worcestershire sauce, and minced garlic into the skillet. Reduce heat to low and simmer until flavors combine and mixture thickens to desired consistency, 15 to 20 minutes.
