Last week Mr Falk described Israel's blockade of Gaza as a war crime
The Israeli authorities have prevented a senior UN human rights official from entering the country, accusing him of being seriously biased against it.
Israel has been angered by a series of comments by Richard Falk accusing it of war crimes and comparing its actions in Gaza to Nazi Germany in WWII.
Mr Falk was stopped at Tel Aviv airport on Sunday and sent back to the United States on Monday morning.
An official accused him of following a distorted, anti-Israeli mandate.
"[He] does not try to advance human rights, but instead comes with his conclusions ready and those conclusions are of course extreme, methodic criticism of Israel and only of Israel," said foreign ministry spokesman Yigal Palmor.
A spokeswoman for the interior ministry spokeswoman said the former Princeton University international law professor had been told he would be turned back if he flew to Israel.
Local human rights group Adalah criticised Israel's decision to deport Mr Falk, calling it a "severe blow to the rights of the Palestinian civilian population living under Israeli occupation".
Last week Mr Falk, the special human rights rapporteur for the occupied Palestinian territories, described the Israeli blockade of Gaza as a massive violation of international humanitarian law.
"Israel maintains its Gaza siege in its full fury, allowing only barely enough food and fuel to enter to stave off mass famine and disease," he said in a statement to the UN Human Rights Council.
Israel says its blockade is a necessary security measure to stem rocket attacks from the territory, whose borders are controlled by Israel but which is controlled internally by the Hamas militant group.