The National Security Service (Turkish: Milli Emniyet Hizmeti, MEH, but known as MAH) was the governmental intelligence organization of Turkey between 1926 and 1965, when it was replaced by the National Intelligence Organization (Turkish: Millî İstihbarat Teşkilâtı, MİT).
It was established at a time when Mustafa Kemal Atatürk was purging Committee of Union and Progress elements, including the Karakol society and Teşkilât-ı Mahsûsa ("Special Organization") intelligence organizations. The first director of the MAH was Şükrü Âli Ögel (1886–1973).