Sir James Percy Miller, 2nd Baronet DSO (22 October 1864 – 22 January 1906) was a British soldier, known as a racehorse owner. Over the 17 years when he had horses in training, Miller won 161 races, worth £114,005.
Miller was the eldest surviving son of Sir William Miller, 1st Baronet, by Mary Anne, daughter of John Farley Leith, a Queen's Counsel and Member of Parliament for Aberdeen. He was educated at Eton College and Sandhurst.
Miller was a Captain in the 14th Hussars from 1885 to 1892, and Adjutant from 1888 to 1892; and served in the Second Boer War from 1900 where in 1901 he was second in command of the sixth battalion, Imperial Yeomanry. He was made an Hon. Major in the army in 1901 and became a full Major in the Lothians and Berwickshire Imperial Yeomanry from March 1902. He was mentioned in dispatches, and was awarded the Distinguished Service Order.
Miller was a Deputy Lieutenant and Justice of the Peace for Berwickshire. His father's fortune, made from herring, allowed Miller to commission the complete rebuild of Manderston House as a stately home, near Duns, Berwickshire. His town residence was 45 Grosvenor Square, Belgravia, London.
On 22 January 1906, Miller died at Manderston. His remains were interred at Christ Church, Duns.