Nasir al-Din (Arabic: نصیر الدین or ناصرالدین or نصر الدين, 'Defender of the Faith'), was originally a honorific title and is an Arabic masculine given name. There are many variant spellings in English.
Notable people with the title or name include:
Politics and government
- Nasir ad-Din Mahmud I of Great Seljuq, sultan of the Seljuk Empire 1092–1094
- Al-Afdal Shahanshah (1066–1121), Fatimid vizier of Egypt, nicknamed Nasir al-Din
- Nasir ad-Din Qabacha, Muslim Turkic governor of Multan from 1203
- Nasir al-Din Mahmud (reigned 1201–22), of the Artuqids of Hisnkeyfa
- Nasiruddin Mahmud (son of Iltutmish) (died 1229), ruler of Bengal
- Nasir ad-Din Mahmud, Zengid Emir of Mosul 1219–1234
- Nasir ad-Din al-Malik al-Mansur Ibrahim bin Asad ad-Din Shirkuh (died 1246), emir of Homs under the Ayyubid dynasty
- Nasiruddin Mahmud (grandson of Iltutmish) (1246–1266), Muslim Turkic ruler and Sultan of Delhi
- Al-Malik al-Said Nasir al-Din Barakah (1260–1280), Mamluk Sultan of Egypt and Syria
- Nasiruddin Bughra Khan, governor and then Sultan of Bengal (1281–1291)
- Nasr al-Din (died 1292), a provincial governor of Yunnan in China during the Yuan dynasty
- Al-Nasir Nasir al-Din Muhammad ben Qalawun, or just Al-Nasir Muhammad (1285–1341), Mamluk sultan of Egypt
- Syed Nasiruddin, a Sufi saint and military leader associated with the spread of Islam in Bengal in the 14th century
- Nasir al-Din Muhammad (died c. 1318), Mihrabanid malik of Sistan
- Nasir ud din Muhammad Shah III, a ruler of the Tughlaq dynasty 1390–1394
- Nasir-ud-Din Mahmud Shah Tughluq, the last sultan of the Tughlaq dynasty to rule Delhi, 1394–1413
- Nasir-ud-din Nusrat Shah Tughluq, a ruler of the Tughlaq dynasty
- An-Nasir ad-Din Muhammad (1411–1422), the son of Sayf ad-Din Tatar, and a Mamluk sultan of Egypt 1421–1422
- Nasiruddin Mahmud Shah of Bengal (died 1459), sultan of Bengal
- Nasiruddin Nasrat Shah (died 1532), sultan of Bengal
- Nasir ad-Din al-Qasri Muhammad ibn Ahmad (died 1547), the young son of the Sultan of Fez, Sultan Ahmad
- Nasir ud-din Muhammad, or Humayun (1508–1556), Mughal Emperor
- Nasr ad-Din (died 1674), leader of the Berber tribes during the Char Bouba war
- Nasruddin (reigned 1690–1710), 15th Sultan of Brunei
- Nasir-ud-Din Haidar Shah (1803–1837), King of Oudh
- Naser al-Din Shah Qajar (1831–1896), Shah of Persia
- Nasruddin Khan, emir of Kokand 1875–1876
- Ismail Nasiruddin of Terengganu (1907–1979), Yang di-Pertuan Agong of Malaysia
- Amal Nasser el-Din (born 1928), Druze Israeli author and politician
- Nasiruddin Khan (c. 1948 – 2018), an Indian politician from West Bengal
- A J M Nasir Uddin (born 1957), Bangladeshi politician
- Nasser al-Din al-Shaer, or Nasser al-Shaer, (born 1961), Palestinian politician
- Ghazi Nasr Al-Din (born 1962), Venezuelan diplomat and alleged Hezbollah supporter
- Nasiruddin Ahmed Pintu (1967–2015), Bangladeshi politician
- Mir Mohammad Nasiruddin (fl. from 1990s), Bangladeshi politician
- Nasir Uddin Chowdhury (fl. from 1990s), Bangladeshi politician
- Nasruddin Mohseni (fl. from 2002), Afghan politician
- Nasir Uddin (Naogaon politician) (died 2017), from Bangladesh
- Nasir Uddin (Jessore politician) (fl. from 2018), from Bangladesh
Scholars and writers
- Nasreddin or Nasreddin Hodja, 13th century Seljuq satirist, populist philosopher, Sufi and wise man
- Sayyed Nasir-ud-deen Abu Yusuf Bin Saamaan (1038–1067 CE), Sufi Saint
- Sheykh Nasreddin Abul Hakayik Mahmud bin Ahmed al-Hoyi, or Ahi Evren (1169–1261), Turkish Muslim preacher
- Nasir al-Din al-Tusi (1201–1274), Persian scientist, mathematician, philosopher, physician and theologian
- Nasiruddin Chiragh Dehlavi (1274–1356), mystic-poet and Sufi saint
- Nasiruddin Sailani Badesha (died 1507), Sufi saint
- Muhammad Nasiruddin al-Albani (1914–1999), Syrian-Albanian Islamic scholar
- Nasir al-Din Nasir Hunzai (born 1917), Pakistani writer and poet
- Naseeruddin Naseer Gilani (1949–2009), a Pakistani poet and Islamic scholar of the Chishti Sufi order
- Nasreddin Lebatelier, pseudonym of Yahyah Michot (fl. from 1995), Belgian Muslim writer
Sports
- Shaikh Nasiruddin (1916-1991), an Indian cricketer
- Nasreddine Akli (born 1953), Algerian footballer
- Nor Saiful Zaini Nasir-ud-Din (born 1966), Malaysian hockey player
- Alain Nasreddine (born 1975), Canadian ice hockey player
- Nasreddine Kraouche (born 1979), Algerian footballer
- Ali Nasseredine (born 1983), Lebanese footballer
- Nasiruddin Faruque (born 1983), Bangladeshi cricketer
- Nasserredine Fillali (born 1984), Algerian boxer
- Nasiruddin Chowdhury (born 1985), Bangladeshi footballer
- Nasr Eldin El Shigail (born 1985), a Sudanese footballer
- Nasreddine Megdich (born 1991), Qatari handball player
- Nadhirah Nasruddin (born 1994), Malaysian cricketer
Other people
- Mohammad Nasiruddin (1888–1994), Bangladeshi journalist
- Advocate Nasiruddin (1892–1949), lawyer and political and social leader from Bhopal, India
- Naseeruddin Mauzi (died 1920), Indian Khilafat Movement activist
- Nasreddin Murat-Khan (1904–1970), Russian-born Pakistani architect
- Naseeruddin Shah (born 1949), Indian film actor and director
- Mohamed Nasr Eldin Allam (born c. 1954), Egyptian water engineer and politician
- Nasreddine Dinet (1861–1929), French orientalist painter
- Naseeruddin Saami (fl. from 1950s), classical singer from Pakistan
- Nasiruddin Yousuff (fl. from 1973), Bangladeshi stage and film director
- Nasrdin Dchar (born 1978), Dutch-Moroccan actor
- Nasir Uddin (anthropologist) (born c. 1978), Bengali anthropologist
- Attia Nasreddin, Ethiopian businessman
- Nasiruddin Nasir (born 1992), Malaysian actor