Celtuce (Lactuca sativa var. asparagina, augustana, or angustata), also called stem lettuce, celery lettuce, asparagus lettuce, or Chinese lettuce, is a cultivar of lettuce grown primarily for its thick stem, used as a vegetable. It is especially popular in China, where it is the most common form of lettuce, and is called wosun (Chinese: 莴笋; pinyin: wōsŭn) or woju (Chinese: 莴苣; pinyin: wōjù) (although the latter name may also be used to mean lettuce in general).

The stem is usually harvested at a length of around 15-20 cm and a diameter of around 3-4 cm. It is crisp, moist, and mildly flavored, and typically prepared by slicing and then stir frying with more strongly flavored ingredients.