John Grubham Howe (1657–1722), commonly known as Jack Howe, was an English politician. Elected on numerous occasions as Member of Parliament, he made the transition from the Whig to the Tory faction.
He was second son of John Grobham Howe of Langar, Nottinghamshire, who was member of parliament for Gloucestershire. His mother was Annabella, third and youngest illegitimate daughter and coheiress of Emanuel Scrope, 1st Earl of Sunderland. Early in life he figured as a young and amorous courtier. In 1679 he brought an accusation against Frances Stewart, Duchess of Richmond, which on investigation proved to be false, and he was forbidden to attend the court. At this period he wrote verses.
Following the Glorious Revolution he sat for Cirencester in the Convention parliament, January 1689 to February 1690, and in its two successors 1690-5 and 1695-8. The county of Gloucester returned him in 1698, and again in January 1701. At the subsequent election (December 1701) the Whigs concentrated efforts against him and ejected him from the seat. In Queen Anne's first parliament (1702) Howe was returned for four constituencies (Bodmin, Gloucester city, Gloucester county, and Newton in Lancashire); and chose his old seat for Gloucestershire. A petition by Sir John Guise, his opponent for the county, against his return was defeated by 219 votes to 98. After 1705 he ceased to sit in parliament.