Jaime Lachica Sin (31 August 1928 – 21 June 2005) (Chinese name: ???; ??? X?n H?iméi; X?n H?imián) was the Roman Catholic Archbishop of Manila. A Chinese Filipino, Sin was known for his instrumental role in the People Power Revolution which toppled the regime of Ferdinand Marcos and installed Corazon Aquino as president of the Philippines. During his reign, he was considered an influential and charismatic leader of the Filipino people having led another "people power" revolution in 2001. He died at the age of 76, due to complications to his kidneys as a result of diabetes.

Sin was the third native Filipino Archbishop of Manila, following centuries of Spanish, American and Irish episcopacy. He led the Archdiocese of Manila as its archbishop and was created a cardinal by Pope Paul VI. As Archbishop of Manila, he was widely considered to be the Primate of the Philippines, though no formal dignity has ever been attached to the archdiocese. He retired as the Archbishop of Manila on 15 September 2003, having reached the age of retirement for bishops under canon law, and was succeeded by Gaudencio Rosales.

His title and surname as Cardinal Sin (another term for a deadly sin) were a point of humour in the Philippines and for Philippine Catholics. Examples included "The greatest sin of all: Cardinal Sin", and even his own pun of "Welcome to the house of Sin" that he said to guests at his official residence of Villa San Miguel.