Henry Denis Hauenstein, MM (3 May 1881 – December 1940) was a rower who competed for Australasia at the 1912 Summer Olympics. He participated in the Men's eight.
Hauenstein was a member of Leichhardt Rowing Club. He was the Club's first eight-oared representative and rowed in the New South Wales (NSW) of 1907, 1908, 1909, 1910 and 1911. NSW was won in 1908, 1910 and 1911. He rowed at the Peace Regatta at Henley-on-Thames in 1919 when the Australian Imperial Force (AIF) crew won the King's Cup.
In 1915, he enlisted with the First Australian Imperial Force and rose to the rank of Lieutenant. He was awarded the Military Medal.