Costume jewelry is jewelry that is made of less valuable materials, including base metals, glass, plastic, and synthetic stones, in place of more valuable materials such as precious metals and gems. These items are usually, but not always, inexpensive, and often flashy. Costume jewelry is mainly used for fashion purposes, opposed to "real" (precious) jewelery which may exist primary as collectables, keepsakes, or investments.

Costume jewelry gets its name from its use in stage costumes. See fashion jewelry

Costume jewelry can vary from vintage rhinestone sets to the latest fashions such as hair accessories and body jewelry with imitation stones.

Coco Chanel greatly popularized the use of faux jewelry in her years as a fashion designer, bringing costume jewelry to life with gold and faux pearls.

Pennino Brothers Jewelry is one rare, but well-known brand of costume jewelry.