John Black Packer (March 21, 1824 – July 7, 1891) was a Republican member of the U.S. House of Representatives from Pennsylvania.
John B. Packer was born in Sunbury, Pennsylvania. He received private instructions and later attended Sunbury Academy in Sunbury, Pennsylvania. He was a member of the corps of engineers employed by the State in the survey and construction of public improvements from 1839 to 1842. He studied law, was admitted to the bar on August 6, 1844, and commenced the practice of his profession in Sunbury. He was also engaged in banking. He served as deputy attorney general from 1845 to 1847. He served in the Pennsylvania State House of Representatives in 1850 and 1851. He was one of the organizers of the Susquehanna Railroad Company in 1851.
Packer was elected as a Republican to the forty-first and to the three succeeding Congresses. He served as chairman of the United States House Committee on Railways and Canals during the Forty-second Congress and United States House Committee on Post Office and Post Roads during the Forty-third Congress. He declined to be a candidate for renomination in 1876. He resumed the practice of law in Sunbury and resumed his banking activities. He died in Sunbury in 1891. Interment in Pomfret Manor Cemetery.