In large pot, heat oil over medium heat. Add onion and cook , stirring often, until soft, about 7 minutes. Add okra and potatoes and cook, stirring often, 5 minutes longer. Season with salt and pepper.
Add stock and lentils. Bring to a boil, then reduce heat and simmer, covered, until lentils are tender about 30 minutes. Add carrots and peas and cook 10 minutes more. Serve hot.