Joanna Miriam Hewitt AO (born 1 May 1949) is a former senior Australian public servant and policymaker.

[4] Hewitt joined the Australian Public Service in 1972 as a trainee at the Department of Foreign Affairs.

[7] She stayed in the role until 2007, resigning to join her husband in Washington DC who had a posting there.

[9] Hewitt was made an Officer of the Order of Australia in 2008 for service to the community, particularly through significant contributions to Australia's agricultural, forestry and fishing sectors, to cross departmental policy formulation and delivery, and to international relations through fostering diplomatic, trade and cultural interests'.

[3] In late 2016, the Department of Foreign Affairs and Trade named one of its 16 meeting rooms in honour of Hewitt, in recognition of her work as a pioneering female diplomat.