Sir Montagu Lowther Chapman (19 December 1808 – 17 May 1852) was an Anglo-Irish landowner and Member of Parliament (MP).
He was born at Killua Castle, Westmeath, the son of Sir Thomas Chapman, 2nd Baronet and educated at Trinity College, Dublin.
[2] In that same year he visited Australia and on 14 June 1842 was granted title to a large estate near Adelaide, which he leased out as smaller farms.
He was last seen in 1852 on a sea voyage from Melbourne to Sydney, when the vessel in which he was sailing disappeared without trace.
He had never married and his Irish and Australian estates were inherited by his younger brother Sir Benjamin James Chapman, 4th Baronet.