"God willing we will liberate Al-Quds (Jerusalem) together and pray together there," Meshaal told students at the University of Tehran on the third day of a visit to Iran.
"We are fully preparing ourselves to liberate all of Palestine, retake Al-Quds (Jerusalem) and secure the return of all Palestinians," he said in an address delivered in Arabic, which was translated into Farsi.
Israel rejects the political legitimacy of the Hamas rulers of the Gaza Strip and fought a 22-day war with the Islamist movement which ended in mutual ceasefires on January 18.
The Jewish state said its onslaught on Hamas, which killed more than 1,300 Palestinians, was aimed at halting rocket fire into southern Israel by Gaza-based militants.
Israel has long accused Iran of arming the Islamists in Gaza, a claim Tehran denies even though it says it offers moral support to Hamas.
The Damascus-based Meshaal said he had also held talks with Iran's supreme leader, Ayatollah Ali Khamenei, over possible Iranian help in reconstructing Gaza Strip, which was devastated during the Israeli onslaught.
"We met (Khamenei) and reached agreement on how Iran can help in rebuilding Gaza," Meshaal said.
The Israeli assault devastated wide swathes of the impoverished and densely populated Palestinian enclave, already reeling under a punishing Israel blockade imposed after the Hamas takeover of the territory in June 2007.
After meeting Khamenei on Sunday, Meshaal ruled out a permanent ceasefire unless Israel lifts the blockade.
One Palestinian militant was killed on Monday by an Israeli air raid on Gaza where Hamas has said it favours a conditional one-year truce on condition the territory's crossings are opened to the outside world.
