Marrying a Turkish citizen does not bring Turkish citizenship on its own. However, foreigners who want to obtain Turkish citizenship by marrying a Turkish citizen can apply to the most powerful civilian administrations inside country and Turkish consulates abroad in a written way provided that they have been married and have actually been living together for at least three years and they have been continuing their marriage. As a result of the enquiries and investigations to be conducted by the Interior Ministry upon application, persons who are deemed to bear the required conditions obtain Turkish citizenship following the date of the relevant decision.
However, if a foreigner married a Turkish citizen loses his/her ex-citizenship due to the marriage, he/she obtains Turkish citizenship automatically. 
Those who obtained Turkish citizenship through marriage continue to have Turkish citizenship if they are pure-minded in contract if marriage is decided to be nullified. 
Children of a marriage born before nullification continue to have their Turkish citizenships even if their mother or father is not pure-minded.