Ann Siang Hill (Chinese: 安详山) is a small hill, and the name of a one-way road located in Chinatown within the Outram Planning Area in Singapore. The road links Club Street and Ann Siang Road (安祥路) to South Bridge Road.
Ann Siang Road connects Ann Siang Hill to Kadayanallur Street.
Ann Siang Hill, located off South Bridge Road, was the site of the house and estate of Chia Ann Siang (谢安祥; 1832–1892), a wealthy Malacca-born Hokkien Chinese sawmiller. Chia joined British firm Boustead and Company (now known as Boustead Singapore today) in 1848. The company traded in natural resources, spices, coconut, tobacco, tin, tea and silk. Boustead's ships plied the China-Europe routes in the early days. After eight years on the job, Chia was promoted to chief produce storekeeper. He retired in 1890 after over 40 years of service in the company, and went into the timber business. He also became a partner of the firm Geok Teat and Company in 1863. After he became a wealthy landowner and one of the leading merchants of his time, he acquired both Ann Siang Hill and Mount Erskine.
Before Chia bought the area, the hill was known as Gemmill's Hill after John Gemmill, a merchant and former auctioneer, and before that Scott's Hill, after its original owner Charles Scott, who cultivated nutmegs and cloves in the area.