The Chamberlin is an electro-mechanical keyboard instrument related to the Mellotron. It was created by Harry Chamberlin in 1946.

The principle of the instrument is that underneath each key is a small tape deck. When you press down a key, the tape deck begins to play. When you release the key, the tape rewinds. Each tape is only a few seconds long (on many units 8 seconds). The tape can have several tracks allowing you to choose from a few different instruments.

Some controversy exists about the origin of the Mellotron, but most of the accounts tell of a Chamberlin associate (sometimes described as his gardner, sometimes as an employee) Bill Fransen bringing Chamberlin's design to England and selling the design without Chamberlin's knowledge in the early 1960s. Chamberlin and the company that produced Mellotrons later came to a financial arrangement.

The royalties Chamberlin received from the Mellotrons helped him to continue to produce Chamberlins in his garage and later in a factory in Ontario, Canada. They ceased production, after making approximately 700 units, in 1981 shortly before Harry Chamberlin's death. The original tapes and supplies were eventually sold by Harry Chamberlin's son, Richard, to the surviving United States Mellotron company.

The later Chamberlin model M1 is reputed to have superior sound and reliability to Mellotrons. It is rumored that several famous recordings which purportedly use a Mellotron actually use a Chamberlin. One popular music group that openly used a Chamberlin is Ambrosia.