Muhteşem Yüzyıl: Kösem (Turkish pronunciation: [muhteˈʃæm ˈjyzjɯl cøˈsæm], lit. 'Magnificent Century: Kösem') is a Turkish television sequel to the 2011 Turkish television period drama, Muhteşem Yüzyıl. Written by Yılmaz Şahin, it recounts the life of Mahpeyker Kösem Sultan, the most powerful woman in Ottoman history who was part of the Sultanate of Women. Actresses Nurgül Yeşilçay, Beren Saat and Anastasia Tsilimpiou played the title role in three different ages of her life, while actors Ekin Koç, Boran Kuzum, Taner Ölmez, Metin Akdülger and Tugay Mercan were cast as different sultans of the Ottoman dynasty. Also in the starring cast were actresses Hülya Avşar, Tülin Özen, Leyla Feray, Farah Zeynep Abdullah, Aslıhan Gürbüz and Hande Doğandemir, who played prominent roles of different sultanas in the series.

The first few episodes of the series were filmed in Chios, Greece. An excerpt of the show was screened in Cannes, France, at the annual international television festival MIPCOM about a month before its official premiere on Star TV on November 12, 2015. It was later transferred to FOX for its second season. Since its broadcast, Muhteşem Yüzyıl: Kösem has been aired in several countries.

Its final episode aired on 27 June 2017. The series' finale marked the end of the six-year Muhteşem Yüzyıl saga.