International Quds Day is an annual pro-Palestinian event held on the last Friday of the Islamic holy month of Ramadan to express support for Palestinians and oppose Israel and Zionism.

The event was first held in 1979 in Iran, shortly after the Iranian Revolution.  

Imam Khomeini the First leader of Islamic Republic of Iran stated that the "liberation" of Palestine  was a religious duty to all Muslims: 

I invite Muslims all over the globe to consecrate the last Friday of the holy month of Ramadan as Al-Quds Day and to proclaim the international solidarity of Muslims in support of the legitimate rights of the Muslim people of Palestine. For many years, I have been notifying the Muslims of the danger posed by the usurper Israel which today has intensified its savage attacks against the Palestinian brothers and sisters, and which, in the south of Lebanon in particular, is continually bombing Palestinian homes in the hope of crushing the Palestinian struggle. I ask all the Muslims of the world and the Muslim governments to join together to sever the hand of this usurper and its supporters. I call on all the Muslims of the world to select as Al-Quds Day the last Friday in the holy month of Ramadan—which is itself a determining period and can also be the determiner of the Palestinian people's fate—and through a ceremony demonstrating the solidarity of Muslims worldwide, announce their support for the legitimate rights of the Muslim people. I ask God Almighty for the victory of the Muslims over the infidels. 

— Ruhollah Khomeini, 1979