Christmas ornaments are decorations (usually made of glass, metal, wood or ceramics) that are used to festoon a Christmas tree. Ornaments take many different forms, from a simple round ball to highly artistic designs. Ornaments are almost always reused year after year, rather than purchased annually, and family collections often contain a combination of commercially produced ornaments and decorations created by family members. Such collections are often passed on and augmented from generation to generation.

Santa Claus is a commonly used figure. Candy canes, fruit, animals, snowmen, angels and snowflake imagery are also popular choices.

Lucretia P. Hale's story "The Peterkins' Christmas-Tree" offers a short catalog of the sorts of ornaments used in the 1870s:

The modern-day mold-blown colored glass Christmas ornament was originally invented in the small German town of Lauscha in the mid-19th century.