In a medium saucepan combine lentils, bay leaf, and thyme.
Add enough water to cover by 1 inch.
Bring to boil, reduce heat and simmer uncovered until lentils are tender but not mushy, about 16 to 20 minutes.
Drain lentils and discard bay leaf and thyme.
Place in a large work bowl with carrots, celery, red pepper, red onion, parsley, garlic, lemon juice, olive oil, salt and pepper.
Toss to combine and serve chilled or room temperature.