A prop dagger that the comedian used on the set of his 1991 movie "Hook," and battery-powered t-shirt that he wore to the 2000 Academy Awards for a performance of "Blame Canada," are also included in the sale at Sotheby's in New York on Oct. 4.
"We're incredibly excited about the watch that Robin Williams wore during 'Dead Poets Society'," Nina del Rio, Sotheby's vice chairman, told Reuters Television at a public exhibition ahead of the sale.
The gold-plated Hamilton wristwatch, engraved on the back after filming in 1988, is expected to fetch up to $2,000.
The items, including works by modern artists Banksy and Shephard Fairey, were collected by Williams and his second wife Marsha Garces Williams over 20 years. Williams died by suicide in 2014 at age 63.
The auction includes the actor's Golden Globe statuettes for "Good Morning Vietnam" (with an estimate of $15,000-20,000) "Mrs. Doubtfire," "Mork & Mindy" and "The Fisher King."
Sotheby's expects the 300-item sale to raise about $3 million, a portion of which will go to organisations the couple supported including Human Rights Watch and the Wounded Warrior project.