William Hemsley was a British artist who specialised in genre paintings.

William was born in London, the son of architect William Whitfield Hemsley and Caroline Amelia Hemsley. He was sent away to preparatory school in Brighton at a young age, and began to develop an interest in art through painting portraits as a teenager. Upon his return to London, he began to train in his father's profession and found employment as a drawing clerk in the office of John Crake. However, he continued to be drawn to art, and left early in his career in order to paint professionally. He began to exhibit at artistic societies, and his works were regularly reported upon in The Art Journal. Hemsley's technique was compared to the Dutch style, but attention was also drawn to his "love for fun". Many of his works depicted rustic domestic scenes, leading to him being described as "pre-eminently the painter of cottage life".

In 1859, Hemsley was elected to the Society of British Artists, and served as the Vice President of the organisation, which later became the Royal Society of British Artists (RBA), for many years. He was also a steward of the Artists' General Benevolent Institution.

For most of his adult life, Hemsley resided in London, including at 5 Marlborough Street, and at addresses in Chelsea and South Kensington. He also undertook numerous study trips abroad, including to France and Holland.