Josiah Butler (December 4, 1779 – October 27, 1854) was a United States Representative from New Hampshire. He was born in Pelham, New Hampshire. He attended the Londonderry and Atkinson academies and was instructed by private tutors. Later, he graduated from Harvard University in 1803. Upon graduation, he taught school in Virginia for three years. He then studied law and was admitted to the bar of Virginia in 1807. He returned to Pelham and commenced practice in 1807, moving to Deerfield, New Hampshire in 1809.
Butler served as the sheriff of Rockingham County (1810–1813) and then the clerk of the court of common pleas. He was an unsuccessful candidate for election in 1812 to the Thirteenth Congress. He was a member of the New Hampshire House of Representatives in 1815 and 1816 and then was elected as a Democratic-Republican to the Fifteenth Congress and reelected to the Sixteenth and Seventeenth Congresses (March 4, 1817 – March 3, 1823). In Congress, he served as chairman, Committee on Agriculture (Seventeenth Congress). After leaving Congressional service, he served as an associate justice of the New Hampshire Court of Common Pleas 1825–1835. Butler died in Deerfield in 1854. He was buried in Granite Cemetery, South Deerfield.