Sir Allan George Mossop (30 July 1887 – 14 June 1965) was a British judge of South African origin who served in China. He was the Chief Judge of the British Supreme Court for China from 1933 to 1943.

Mossop was born in Fish Hoek, in the Cape Colony in 1887 and was the seventh son of Joseph Mossop. He was educated at the Kingswood College, Grahamstown and the South African College, Cape Town. He then went to university in England attending Pembroke College, Cambridge graduating with an MA and LLB. He was called to the Bar of the Inner Temple in 1908.^[1]

Mossop moved to Shanghai, China soon after being called as a barrister and was admitted to practice before the British Supreme Court for China and Corea in 1909.^{[citation needed][2]}

In 1916, Mossop was appointed the Crown Advocate for Weihaiwei when Hiram Parkes Wilkinson, the Crown Advocate for China who had held that position was appointed Judge in Weihaiwei. In 1926 on Wilkinson's retirement as Crown Advocate for China, Mossop was appointed Crown Advocate for China.^[3] As Crown Advocate, Mossop was allowed to continue private practice as a barrister.^{[citation needed]}

In December 1933, he was appointed Chief Judge of the British Supreme Court for China on the retirement of Sir Peter Grain.^[4] He was knighted in May 1937.^[5]

At the beginning of the Pacific War, on 8 December 1941, Japanese troops occupied the court house of the British Supreme Court in Shanghai. Mossop was interned for 5 months before being repatriated to England.^[6]

His appointment as judge was formally terminated in May 1943 after the Sino-British Treaty for the Relinquishment of Extra-Territorial Rights in China was ratified.^[7]

Mossop returned to China in 1946 as an advisor to the British Embassy in China. He retired in 1947 and returned to his home in Fish Hoek, Cape Town, South Africa. He died on 14 June 1965 in Cape Town.^[8] He was buried in Muizenberg Cemetery, Cape Town.