Centre Giteau, who qualifies to represent his country in spite of playing for a French club because he has won more than 60 caps, was called up despite Australian media reports that Toulon were trying to block the move.
The other overseas-based players included were outside back Adam Ashley-Cooper, scrumhalf Will Genia and winger Drew Mitchell. All four were key members of the Wallabies team that reached the World Cup final last year.
Cheika did not bring the quartet back to Australia for the June series against England, which the Wallabies lost 3-0, but they will now be in contention to face world champions New Zealand in back-to-back tests next month.
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"All of our eligible European-based players expressed a desire to play for the Wallabies during the Rugby Championship and that experience is invaluable," Cheika said. "We have a very clear purpose in this team and we are prepared to work very hard to respect that purpose."
Flyhalf Quade Cooper, who has signed a three-year deal with the Australian Rugby Union after cutting short his spell in France, was also included.
Uncapped prop Allan Alaalatoa and centre Reece Hodge have been in previous squads but prop Tom Robertson and loose forward Lopeti Timani, the brother of former Wallabies lock Sitaleki, received their first call-ups.
Outside back Dane Haylett-Petty, centre Samu Kerevi, scrumhalf Nick Frisby and lock Adam Coleman have all been retained after making their test debuts against England in June.
The Wallabies kick off their campaign against New Zealand at Sydney's Olympic Stadium on Aug. 20.
Squad:
Forwards - Allan Alaalatoa, Adam Coleman, Kane Douglas, Scott Fardy, James Hanson, Michael Hooper, Sekope Kepu, Ben McCalman, Sean McMahon, Stephen Moore, Dean Mumm, David Pocock, Tatafu Polota-Nau, Tom Robertson, Rob Simmons, Scott Sio, Will Skelton, James Slipper, Toby Smith, Lopeti Timani.
Backs - Adam Ashley-Cooper, Quade Cooper, Israel Folau, Bernard Foley, Nick Frisby, Will Genia, Matt Giteau, Dane Haylett-Petty, Reece Hodge, Rob Horne, Samu Kerevi, Tevita Kuridrani, Drew Mitchell, Luke Morahan, Nick Phipps, Matt Toomua.
(Reporting by Nick Mulvenney; Editing by Sudipto Ganguly)
