An anonymous buyer paid more than $3m (£1.5m) for it.
It was deemed to be the window from the Texas Schoolbook Depository that Oswald shot from.
The starting bid was $100,000 but soon escalated and the item was sold for $3,001,501.
The depository had been owned by a Dallas family that listed the item on eBay.
There was no evidence that was window was indeed, the one that Lee Harvey Oswald allegedly shot from.