Heat olive oil in a large stockpot. Add carrot, onion, celery, garlic, thyme, lemon rind and salt; sauté over medium heat until vegetables begin to soften.
Add chicken stock and lemon juice. Bring to a boil.
Add chicken and orzo. Simmer for 12 minutes or until orzo is cooked through, stirring constantly so orzo does not stick to the bottom of pan. Season with salt and pepper to taste. Serve with chopped parsley.