Lennon reportedly gave the tooth, which is discoloured and contains a cavity, to his housekeeper Dorothy "Dot" Jarlett in the mid-1960s just after having it removed by a dentist.
Dot's son Barry Jarlett told CNN: "She was very close with John, and one day whilst chatting in the kitchen, John gave my mother the tooth and suggested giving it to my sister as a souvenir, as she was a huge Beatles fan. It has been in the family ever since."
Barry said that Lennon gave his mother many gifts over the years, such as a pearl necklace he picked up while vacationing in Japan.
No DNA tests have been done on the tooth because it's in very fragile condition.
The late Beatle's tooth will go under the hammer at the Omega Auction on November 5 and is expected to fetch at least $16,000 (£10,000).
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Listen to The Beatles' song 'Savoy Truffle', which is about cavity-causing confections, below: