General William Mesny (1842 – 11 December 1919) was an adventurer and writer born on the island of Jersey but spent most of his childhood in Alderney, the family home of the Mesnys. He was the eldest of three children of William Mesny and Mary Rachel Nicolle.
Mesny left home at the age of twelve to sail the oceans until finally, after visiting India and Australia, he settled in a turbulent China in 1860. He served with two of the provincial armies of the Qing dynasty imperial military as a mercenary or, in modern parlance, a foreign adviser.
He spent 59 years in China. He became a Major-General in the Imperial army in 1873 when he was only 30, suggesting that his services were greatly valued by the Chinese. He was also made a "Knight Ying of the Order of the Pa-tu-lu", the Chinese equivalent of the French Legion d'honneur. In 1890 he was awarded the decoration of the Pao Hsing (the Star of China).
He always retained British citizenship and was a Fellow of the Royal Geographical Society, the Royal Horticultural Society, and of the Imperial Institute. At one time he was the senior adviser to the Commander-in-Chief of the Chinese armed forces and was given the title of Brevet Lieutenant-General, Chinese Army.
He visited almost every part of China, including Xinjiang. He also visited Tonking (now northern Vietnam) and accompanied Captain William Gill on his expedition in 1877 from Chengdu to Burma via Litang, Batang, Dali, along the Tibetan borderlands to Bhamo. He was a plant collector and sent specimens back to the British Consul in Canton, Dr. Henry Fletcher Hance, a famous botanist. One species, Jasminum mesnyi, was named after him.