Sir William Watson, FRS (3 April 1715 – 10 May 1787) was a British physician and scientist who was born and died in London.

In 1746, he showed that the capacity of the Leyden jar could be increased by coating it inside and out with lead foil.

He acknowledged that the same theory had been independently developed at the same time by Benjamin Franklin—the two men later became allies in both scientific and political matters.

He also suggested that electricity is more akin to magnetism and light than to a fluid, since it passes through glass and cloth, and can be concentrated as a spark to light up flammable materials.

On 14 August 1747 he made an experiment to conduct electricity through a 6,732 foot long wire at Shooter's Hill in London.