The 47-year-old, who took the job in 2013, will lead Australia's World Cup defence in England before they attempt to win an away Ashes series for the first time since 2001.
"That will be it," Lehmann said. "It will be a case of too much time, too much travel.
"I've really enjoyed the role and am loving it," added Lehmann, who played 27 tests and 117 one-day internationals for Australia as a prolific middle-order batsman.
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"We'll just get to that point and work out what we do from there."
Australia clinched the current series against England last week with victory by an innings and 41 runs in the third test in Perth.
The fourth test starts on Tuesday in Melbourne.
(Reporting by Ed Osmond in London; Editing by Hugh Lawson)
