A prairie skirt is an American style of skirt, an article of women's and girls' clothing.

Prairie skirts are slightly flared to very full, with one or more flounces (deep ruffles) or tiers, and are often worn over a ruffled eyelet or lace-trimmed petticoat. They were introduced to fashion by Ralph Lauren in his fall 1978 Western-themed collection.

Prairie skirts are so-called after their resemblance to the home-sewn skirts worn by pioneer women in the mid-19th century, which in turn are a simplified version of the flared, ruffled skirts characteristic of high-fashion dresses of the 1820s.

In keeping with their design inspiration, traditional prairie skirts are usually made of "country" fabrics such as denim and flowered calico. Prairie skirts are a staple of women's western wear, and very full prairie skirts are worn for square dancing.

Mid-calf length, button-front denim prairie skirts with a single flounce, worn with a petticoat that was slightly longer than the skirt, became a mainstream fashion in the 1970s and early 1980s following Lauren's introduction.