In a saucepan combine lentils, carrots, onion, garlic, bay leaf, and thyme. Add enough water to cover by 1 inch.
Bring to boil, reduce heat and simmer uncovered for 15 to 20 minutes or until lentils are tender but not mushy.
Drain lentils and vegetables and remove bay leaf. Add olive oil, lemon juice, celery, parsley, salt and pepper. Toss to mix and serve at room temperature.