Unnithan is one of the aristocratic Nair caste surnames used mainly in the Travancore region of the present-day Indian state of Kerala.
[1][2] The Unnithan and Valiathan surnames originated from the title "Thānkal" (Malayalam: "താങ്കൾ"), which is a respectful designation used to address members of aristocratic families in Kerala.
[3] According to legend, Maharajah Marthanda Varma of Travancore sought the help of certain Nair families to overcome the powerful Nair clan of Ettuveetil Pillamar, the Lords of the Eight Houses.
[4] Unnithan surname is prevalent mainly in the Kayamkulam region of central Travancore, later due to conflicts between the Kayamkulam Raja and the Unnithan families, they were settled in Kollam and Pathanamthitta region of central Travancore.
Unnithan ladies were married by the Rajahs or princes of the royal families such as Mavelikara, Ennakad, Prayikkara etc.