Iraq also banned the student union at Mustansiriyah University, raising questions over Prime Minister Nouri al-Maliki's commitment to free speech.
The government maintains the school was falling under the sway of religious Shiite groups.
Studies at the university were suspended for one week, spokesman Ali al-Dabbagh said in a statement posted on a government Web site.
Al-Dabbagh said the action was taken because of problems caused by "undisciplined individuals." The statement did not provide any further details.
The university has been at the center of a power struggle between al-Maliki and religious Shiite parties, which has had administrative control of the university since the 2003 U.S.-led invasion.
Earlier this week, a small number students demanded a role in governing the university, a protest that led al-Maliki to temporarily close the campus.
Iraq's Higher Education Ministry defended the action, saying it was necessary "to preserve the independence of the university."
"The aim is ... to put an end to any kind of harmful interference at the university. It should be kept free from sectarian or political influence," said Siham al-Shujeiri, a spokeswoman for the ministry.
The university has been the scene of a number of violent attacks, including a January 2007 double car bombing that killed 70 students who were lining up for bus rides home.