File photo: Iraqi Speaker of Parliament Mohamed al-Halbousi speaks with the news media as he departs the Department of State after meeting with Secretary of State Mike Pompeo, in Washington, on March 28, 2019. AP
"The Federal Supreme Court ends the mandate of the President of Parliament" Halbussi, in office since 2018, the court said in a short online statement.
It added that it had also ended the mandate of the Sunni lawmaker, Laith al-Duleimi.
Halbussi has been the highest ranking Sunni official since he became speaker in 2018 of the parliament, which is dominated by Shia parties.
The court began reviewing a case filed against him in February after Duleimi accused him of forging a resignation letter, saying the speaker had changed the date on an older document to force him out of parliament.
Halbussi, whose Taqadom party has 37 members in parliament, has faced growing unease within Iraq's Sunni political sphere.