David Ernest Oldfield (born 1958), Australian politician, is a member of the New South Wales Legislative Council. He grew up in Manly, a beachside suburb of Sydney. In the 1990s he was prominent in municipal politics, representing the Liberal Party on Manly Municipal Council.

In 1996, while working as a senior staffer for Liberal federal MP Tony Abbott, Oldfield secretly founded the One Nation Party in concert with independent MP Pauline Hanson and David Ettridge . He and Ettridge, known as "the two Davids," were seen as the brains behind Hanson's populist rhetoric.

After Hanson lost her seat in 1998, One Nation began to decline, and Oldfield and Ettridge parted company with Hanson. Oldfield won a seat in the New South Wales Legislative Council at the March 1999 state elections, but he was expelled from One Nation by Hanson in 2000 and founded a separate party of which he is president, the One Nation NSW Political Party.