News of the summons was published on the Iranian government website dolat.ir only days after a moderate, Hassan Rouhani, won the presidential election, The Guardian reported Monday.
The summons did not state the charges against Ahmadinejad. It said only that lawsuit had been filed against him by the speaker of Parliament, Ali Larijani.
In February, Ahmadinejad played a videotape during a public session of Parliament that appeared to show Fazel Larijani invoking his politician brother's name for financial gain.
Ali Larijani said Ahmadinejad's action showed the true nature of his character. Fazel Larijani denied the accusations and threatened to sue the president.
Ahmadinejad's influence has waned in his final term in office. Last month his former chief of staff filed to run in the presidential election, but the Guardian Council disqualified his candidacy without reason.
Ahmadinejad is scheduled to appear in court in November.
Rouhani, who takes office in August, is not involved in the lawsuit.