The Iranian student protests of July 1999 (also known as 18th of Tir and Kuye Daneshgah Disaster (Persian: فاجعهٔ کوی دانشگاه) in Iran) (7–13 July) were student protests which were violently repressed by the Basij and Ansar-e Hezbollah. Before the 2009 Iranian election protests, they were the most widespread and violent public protests to occur in Iran since the early years of the Iranian Revolution.

The protests began on 8 July with peaceful demonstrations in Tehran against the closure of the reformist newspaper Salam. Following the demonstrations, a student dormitory was raided by riot police that night during which a student was killed. The raid sparked six days of demonstrations and rioting throughout the country, during which at least three other people were killed and more than 200 injured.

In the aftermath of these incidents, more than seventy students disappeared. In addition to an estimated 1,200–1,400 detainees, the "whereabouts and condition" of five students named by Human Rights Watch who are believed to be detained by Iranian authorities remain unknown.

The protests began on the eve of 9 July 1999 after a peaceful demonstration by a group of students of Tehran University against the closure of the reformist newspaper, Salam, by the press court. The Salam newspaper (Persian: روزنامه سلام) was operated by the Association of Combatant Clerics, the reformist political party to which the then president, Mohammad Khatami belonged. The student groups, which at the time were considered one of the major supporters of Khatami and his reform programs, were protesting in support of Khatami against the closure of the newspaper by the judiciary, which was controlled by the hardline opponents of President Khatami.

On the evening of the protests, "about 400 plainclothes paramilitaries descended on a university dormitory, whispering into short-wave radios and wielding green sticks." The paramilitaries, thought to be Ansar-e-Hezbollah and Basij, began attacking students, kicking down doors and smashing through halls, grabbing female students by the hair and setting fire to rooms. Several students were thrown off of third story balconies "onto pavement below, their bones crushed", and one student paralyzed. According to students' accounts, uniformed police stood by and did nothing. "Witnesses reported that at least one student was killed, 300 wounded, and thousands detained in the days that followed."

The next day, unrest began in earnest, spreading through Tehran and to other cities and continuing for almost a week, with unemployed youths joining the students. The Basij are reported to have disguised themselves as students (wearing jeans, T-shirts, and shaving their faces) and thrown bricks into shop windows to discredit the student demonstrators. The five days of rioting "turned Tehran into a battlefield," and was "inarguably the worst mass disturbance" the Islamic Republic had seen in its 20 years of existence. Running street battles left downtown Tehran "gutted", with burned-out buses, and smashed storefronts.

There were many arrests and injuries, and at least one confirmed fatal shooting, namely that of Ezzat Ebrahim-Nejad. The death of Ebrahim-Nejad was the only one acknowledged by the state-controlled Iranian television, however, major student groups and the foreign media have claimed more than 17 dead during the week of violent protests.^{[citation needed]} Another student Saeed Zeinali disappeared after his arrest by security forces.

Major Iranian cities such as Tabriz, Mashhad, Shiraz and Esfahan were scenes of violent and widespread demonstrations as well. The protests continued at Tabriz University on 11 July 1999 (20th of Tir) and police and hardliners responded similarly in Tabriz universities and schools, entering the universities and brutally attacked students. Four students died in the unrest and many were beaten while in custody.