Lanning Roper (4 February 1912 – 22 March 1983) was an American landscape architect and writer who studied and lived in England.
He was born in West Orange, New Jersey, the son of Willet Crosby Roper (1877–1966), an investment banker, and Florence Emily née Eveleth (1874–1961). His maternal grandfather William Hartley Eveleth (1840–1922) was the Superintendent of the college grounds for Harvard University and Radcliffe College. Roper received an honors degree in Fine Arts from Harvard University in 1933.
He served in the US Navy in World War II, and was in charge of Division 67 on D-Day.
In 1952 he married Primrose Harley (1908–1978) an artist, daughter of Professor Edward Vaughan Berkeley Harley MD MRCP (1863–1923) and Mary Blagden (1869–?). Her paternal grandfather was George Harley and Ethel Brilliana Tweedie was an aunt. Primrose had previously married and divorced from Lt Col John Alfred Codrington (1898–1991), son of Lt-Gen Sir Alfred Edward Codrington
Roper had many garden commissions all over England, and some in Ireland (including Castlemartin), France, Italy, Switzerland and the United States. He was commissioned as Prince Charles' landscape gardener in 1981 to do the grounds at Highgrove House in the Cotswolds. From 1951 to 1957 was on the staff of the Royal Horticultural Society as Assistant to the Editor.