Oscar O'Neill Oxholm (28 April 1809 – 15 October 1871) was a Danish military officer, chamberlain and landowner. He owned Rosenfeldt Manor at Vordingborg from 1841.
Oxholm was the son of Peter Lotharius Oxholm and Ann O'Neill.
Oxholm began is career in the Royal Danish Army at the Foot Guards. In 1848, he was freed from service to serve as adjudant for Frederick CII. He reached the rank of Major-General and was appointed to chamberlain.
Pxholm married Adelaide Maria O'Kelly (1817-1842) in 1842. They had three sons: [[Carl Arthur O'Neill Oxholm (16 September 1843 - 29 March 1914), Fritz Johan Georg O'Neill Oxholm (23 April 1850 - 3 February 1878) and Oscar Siegfred Christian O'Neill Oxholm (31 January 1855 - 30 July 1926).
Oxholm purchased Rosenfeldt Manor at Vordingborg in 1841. He constructed the new main building, two farm buildings and 20 fæstegårde. Designed by Henrik Steffens Sibbern, the main building was built from 1868 to 1870.
He died on 15 Pctpber 1871 and is buried at Kastrup Cemetery.