Colonel Sir Leonard Ropner, 1st Baronet, DL MC (26 February 1895 – 12 October 1977) was a Conservative Party politician in the United Kingdom.
Ropner was the son of William Ropner, third son of Sir Robert Ropner, 1st Baronet. Leonard's grandfather, Sir Robert, had come from Germany in 1857 and founded a fleet of merchant ships; as MP he represented .
He was educated at Oatlands, Harrogate and Harrow, obtaining a scholarship to Clare College, Cambridge and took a degree in Political Economy. He was a director of the family business of Sir R. Ropner and Co., the shipping company.
He enlisted in 1914 in the Royal Artillery and commanded a battery in France, being awarded the Military Cross in 1919. After the war he commanded the Durham Heavy Brigade of the Royal Garrison Artillery in the Territorial Army in the rank of major, and was later appointed their honorary colonel.
At the 1923 general election, he was elected Member of Parliament (MP) for Sedgefield in County Durham, with a majority of only 6 votes over the sitting Labour MP John Herriotts. Ropner held the seat at the 1924 general election with a more comfortable majority of 1,416, but lost to Herriotts at the 1929 general election.