Sir John Austen, 1st Baronet (died 22 March 1742), was a British landowner and politician.
He was the son of Thomas Austen, of South Mimms and Hoxton, by Arabella Forset, the daughter and heir of Edward Forset, of Ashford and Tyburn. His parents were married on 13 October 1673.
He inherited the Manor of Tyburn, or Marylebone, from his mother's family and sold it in 1710 to John Holles, 1st Duke of Newcastle. He was Member of Parliament for Middlesex in the Parliament of England from 1701 to 1702, and in the Parliament of Great Britain from 1708 to 1710 and 1722 to 1727. He was created a baronet in the Baronetage of Great Britain on 16 November 1714.
He also inherited the Manor of Highbury, in Islington, and sold it in 1723. In 1733, he sold the reversion of the Manor of Derhams. He died unmarried on 22 March 1742, and was buried at South Mimms with his sister Arabella, who had died in 1714. The baronetcy became extinct, while probate was granted to Mary Wright, spinster, his residuary legatee.