After the collapse of the Ottoman Empire and the official establishment of the Republic of Turkey on 29 October 1923, changes were made to the administrative system.

Two years later, Ardahan, Beyoğlu, Çatalca, Dersim, Ergani, Gelibolu, Genç, Kozan, Oltu, Muş, Siverek and Üsküdar provinces were transformed into districts.

Four years later, Aksaray, Cebelibereket, Hakkâri and Şebinkarahisar became districts, Mersin and Silifke were merged to form a new province called İçel, and Artvin and Rize were merged to form a new province called Çoruh, bringing the number down to fifty-six.

After this year, there were no changes in the number of provinces for the next 32 years until Aksaray, Bayburt, Karaman and Kırıkkale became provinces in 1989 along with Batman and Şırnak in 1990; Bartın in 1991; Ardahan and Iğdır in 1992; Yalova, Karabük and Kilis in 1995; Osmaniye in 1996, and Düzce in 1999.

After Zonguldak (code 67), the ordering is not alphabetical, but in the order of the creation of provinces, as these provinces were created more recently and thus their plate numbers were assigned after the initial set of codes had been assigned.