Carrots or jicama can be substituted for celery as a raw vegetable snack. Bok choy can be substituted for celery in both raw and cooked dishes. Fennel stalk or cardoon can be used instead of celery in cooked dishes, but care must be taken to cook them much longer.
Chinese celery or kinchay can be substituted for celery in cooked dishes, but Chinese celery has a stronger flavor than regular celery. Chinese celery is often used in stir-fries and soups where its strong flavor is an advantage.
Jicama is a root vegetable common in Mexico. Cardoon is a thistle-like plant that is related to artichokes.