The triptych – a work of art divided into three sections – was initially estimated to fetch £1.2 million at auction, but went for £1 million above the guide price at final hammer.
The work originally hung at The Walled Off Hotel in Bethlehem, a hotel established by the artist located metres away from the West Bank barrier.
While at first glance the work seems to depict a classic landscape, the trio of paintings actually contain a powerful, politically charged message. Closer inspection reveals stormy cliffs and crashing seas littered with bright orange lifejackets and buoys, washed ashore with no survivors in sight.
They are perceived as a reaction to Europe's migrant crisis, in which hundreds of thousands of people fleeing war and conflict have tried to reach the continent on dangerous journeys across the Mediterranean and Aegean seas over the past decade.
Proceeds from the sale will go towards building a new acute stroke unit and children’s rehabilitation equipment for Bethlehem Arab Society for Rehabilitation hospital in Bethlehem.
The Sotheby's sale also included one of only three self-portraits by Dutch painter Rembrandt van Rijn left in private hands, as well as a rare Pablo Picasso drawing of his muse, Marie-Therese Walter.
Scroll through the gallery below for a look at Banksy's work in Gaza and the West Bank: