Sir Roger Therry (22 April 1800 – 17 May 1874) was an Irish-Australian jurist and member of the New South Wales Legislative Council.
Therry was born in Cork, County Cork, Ireland and educated at Clongowes College and Trinity College, Dublin. He was called to the bar in Ireland in 1824 and in England in 1827. His A Letter to the Right Hon. George Canning on the Present State of the Catholic Question, published in 1826 (second edition 1827) probably led to his acquaintance with Canning, who employed him to edit his speeches and prepare them for publication. The Speeches of George Canning (1828) were published after Canning's death with a life of Canning written by Therry. By the influence of Canning's widow and friends Therry was appointed commissioner of the court of requests for New South Wales. and in July 1829 he sailed for Sydney, arriving in November.
Therry was a Roman Catholic, and on his arrival found that most of the Catholics were poor, and few held important positions in Sydney. The Church of England (now known as the Anglican Church) was comparatively well subsidised by the state, but very little was allowed to the Roman Catholic clergy. He endeavoured with considerable success to improve their position, and for the next 30 years held an important place amongst Catholics. He was made a magistrate in April 1830. and in 1839 refused an acting judgeship. Governor George Gipps, in a dispatch notifying this to Lord Glenelg, referred to Therry as one of the "two most distinguished barristers of New South Wales".
Therry was appointed acting attorney-general in May 1841, and at the first election for the New South Wales Legislative Council held in 1843 he was elected as the representative of the County of Camden. during this time Therry commissioned Keera Vale House, a Georgian mansion recorded as Wollongong's oldest standing house, built 1844. In December 1844 Therry was appointed resident judge at Port Phillip District and held the position until February 1846, when he became a judge of the supreme court of New South Wales. He visited England in 1847, was nominated to the new Legislative Council on 22 May 1856, (now the upper house of the New South Wales parliament) and retired on a pension in 1859, in England.