Lieutenant General Jack Farj Rafael Jacob PVSM (2 May 1921 – 13 January 2016) was a prominent Indian military officer. He was best known for his role in the Bangladesh Liberation War of 1971. Jacob, then a major general, served as the chief of staff of the Indian Army's Eastern Command. During his 36-year long career in the army, Jacob fought in World War II and the Indo-Pakistani War of 1965. He later served as the governor of the Indian states of Goa and Punjab.

In May 1951, Jacob was selected to attend the Defence Services Staff College, Wellington, the staff course started in October of the same year.^[10] As the first commanding officer, he raised 3 Field Regiment on 14 May 1956. On 20 May 1964, he was given command of an artillery brigade, with the acting rank of brigadier. During the Indo-Pakistani War of 1965, he commanded an Infantry Division, which later became the 12th Infantry Division, in the state of Rajasthan. During this period, Jacob composed an Indian Army manual on desert warfare.