There are both Turkish and foreign banks in Turkey.
Some of the biggest Turkish banks are Garanti Bankası, Yapı Kredi Bankası, Türkiye İş Bankası (Isbank), and Akbank. You are guaranteed to find a branch of one of these banks near where you are living, no matter what part of Turkey you are residing. Garanti Bankası offers English-speaking staff at most branches.
Most banks operate between 9:00 and 17:00. Some Turkish banks remain open during lunch hours, and some have branches that are open all year long including the public holidays. These branches are usually located at the central and big shopping malls.
In order to open an account, you will first need to register for a Tax Number. Most banks will require that you have a residency permit before you can open an account in Turkish lira. If you do not have a residency permit, most banks can open you an account in euros, British pounds or US dollars.
ATMs dispense new Turkish lira to Visa, MasterCard, Cirrus and Maestro cardholders. Most machines offer instructions in English, French, and German.
US Dollars and Euros are the easiest currencies to change. Visa and Master Cards are widely accepted by hotels, shops, bars, and restaurants. It is easy to change major currencies in exchange offices, some post offices (PTT), and banks.
Below are the websites of some major banks in Turkey:
Yapı Kredi Bankası