Anne Lauvergeon's appointment will take effect from 15 March 2014. She has over 30 years' experience across a number of fields.
Simon Thompson's appointment will take effect from 1 April 2014. He holds a degree in geology and brings a wealth of international investment banking and mining experience.
The boards also announce the retirement of Vivienne Cox as a non-executive director at the conclusion of the Rio Tinto plc annual general meeting on 15 April 2014.
Rio Tinto chairman Jan du Plessis said "I am delighted to welcome Anne Lauvergeon and Simon Thompson to the Rio Tinto boards. They boast impressive track records as executives across multiple industries, in addition to which both bring a wealth of experience as non-executive directors of a number of leading international businesses.
"I am very grateful to Vivienne for all her support to Rio Tinto over the past nine years and wish her well for the future.
"In addition to the appointments announced today, we are making good progress in identifying another Australian to join the boards as a non-executive and a further announcement in this regard will be made in due course."