Robert Vans Agnew (4 March 1817 – 26 September 1893) was a Scottish Conservative Party politician.
At the 1868 general election he unsuccessfully contested the Wigtown Burghs.
Vans Agnew was elected as the Member of Parliament (MP) for Wigtownshire at a by-election in February 1873, filling the vacancy caused by Lord Garlies succeeding to the peerage. He was re-elected in 1874, and held the seat until he stood down at the 1880 general election.