William Botting Hemsley was an English botanist and 1909 Victoria Medal of Honour recipient.
He was born in East Hoathly, Sussex and in 1860 started work at the Royal Botanic Gardens, Kew as an Improver, then Assistant for India in the Herbarium, finally Keeper of Herbarium and Library. He wrote a number of botanical works.
In 1888, a genus of flowering plants from south-east Asia, belonging to the family Cucurbitaceae was named Hemsleya in his honour.
He was elected a Fellow of the Royal Society in June 1889.