A celesta (pronounced se-lest-a or cheh-lest-a) is a keyboard musical instrument that looks similar to a regular piano. Unlike the piano the notes are not made by striking strings, but by striking metal bars. When keys on the celesta are pressed, hammers inside strike steel metal plates suspended over wooden resonators. A pedal can be used to dampen or sustain the sound.

The plates in a celesta are similar to the metal plates on a glockenspiel. The sounds of the celesta and glockenspiel are quite similar but the celesta has a softer timbre. It is this soft quality sound that helped name the instrument "Celesta". Celeste means "heavenly" in French.

As it makes it sound by striking metal plates, it is treated as part of the percussion section in an orchestra. This is even though it is most often played by a pianist and the music is written on two bracketed staves.

In 1889 the celesta was invented by the Parisian harmonium builder Auguste Mustel. 29 years before (1860), Mustel's father, Victor Mustel, had developed the forerunner of the celesta, the typophone or the dulcitone. This was where tuning-forks were struck instead of metal plates. As the sound produced was not very loud, this was never used in an orchestral situation. Auguste Mustel adapted his fathers works to use metal plates and give it the louder sound required for it to be used in an orchestra.

One of the best known uses of a celesta is in the Dance of the Sugarplum Fairy from Tchaikovsky's ballet, The Nutcracker.