Sir Robert Pye (ca. 1620 – 1701) was an English politician who sat in the House of Commons at various times between 1640 and 1660. He fought on the Parliamentary side in the English Civil War.
Pye was the son of Sir Robert Pye the Elder, Auditor of the Exchequer, and his wife Mary Croker, daughter of John Croker of Batsford in Gloucestershire.
In December 1640, Pye was elected Member of Parliament for in the Long Parliament. He was knighted by 1642. In the Civil War, he became colonel of Horse in General Fairfax's regiment. In the course of the war he besieged his father's mansion at Faringdon in Berkshire (now Oxfordshire), which the latter allowed the royalists to garrison. In 1648 he was excluded from parliament under Pride's Purge.
Pye was elected MP for Berkshire for the First Protectorate Parliament in 1654 and for the Third Protectorate Parliament in 1659. He was involved in the attempt to restore King Charles II. and was appointed one of the treasurers for the money put aside for that purpose. Later he presented a petition from the county of Berkshire, complaining of the lack of a settled form of government and as a result was committed to the Tower of London for a breach of privilege. He moved for an Habeas Corpus, but judge Richard Newdigate decided that the court of King's Bench did not have the power to discharge him. When General Monck came to London, MPs passed a vote to release Pye from prison. In 1660, Pye was elected Member of Parliament for Berkshire in the Convention Parliament and after the Restoration he was nominated equerry to the king.