The Constitutional Court, Turkey's highest court, rejected a plea by an association for the conversion of the Hagia Sophia, an iconic Byzantine-era church currently used as a museum, to a mosque. The court cited technicalities as grounds to reject the bid, saying that there was no "violation of religious freedoms" by the association. Under Turkish laws, such cases can be decided upon only if an individual files a complaint that his or her freedoms are violated.

The Hagia Sophia was built in the 6th century during the Christian Byzantine Empire and served as the seat of the Greek Orthodox Church. It was converted into an imperial mosque with the Ottoman conquest of Istanbul in 1453. The structure was converted into a museum during the strictly secular single-party rule in 1935, but there have been discussions around converting it back to a mosque, with public demands to restore it as a place of worship gaining traction on social media.

In 2015, a cleric recited the Quran inside the building, a UNESCO World Heritage site, for the first time in 85 years. The following year, Turkey's religious authority began hosting and broadcasting religious readings during the holy month of Ramadan and the call to prayer was recited inside on the anniversary of the first revelation of the Quran to the Prophet Muhammad.