Rukn al-Din, Rukn ad-Din or Rukn ud-Din () is a honorific title, now used as a given name. It may refer to:
Abu Muhammad al-Juwayni (died 1046), renowned Islamic scholar. Abu al-Muzaffar Rukn ud-Dīn Barkyāruq bin Malikšāh (died 1105), sultan of Great Seljuq Abbas ibn Abi al-Futuh (died 1154), Fatimid vizier Rukn al-Dīn Mas'ūd, or Mesud I (died 1156), sultan of the Seljuqs of Rûm Rukn ad-Din Suleiman Shah, or Süleymanshah II (1196–1204), Seljuq Sultan of Rûm Rukn al-Din Khurshah (died 1256), 27th Imam of the Nizari Isma'ili Shia community al-Malik al-Zahir Rukn al-Din Baibars al-Bunduqdari (1223–1277), Mamluk Sultan of Egypt and Syria Rukn ud din Firuz (died 1236), Muslim Turkic ruler and Sultan of Delhi Rukn al-Dīn Qilij Arslān bin Kaykhusraw, or Kilij Arslan IV (died 1266), Seljuq Sultan of Rûm al-Malik al-Muzaffar Rukn al-Din Baibars al-Jashnakir al-Mansuri, or Baibars II (died 1309), Mamluk Sultan of Egypt Baybars al-Mansuri (died 1325), Mamluk-era historiographer Sheikh Rukn-ud-Din Abul Fath, also known as Rukn-e-Alam (1251–1335), Indian Sufi saint Rokneddin Mokhtari (1887–1970), Iranian musician and violinist Rukniddin Sharipov (born 1974), Tajik interned in Guantánamo Bay