Dharma Raja Karthika Thirunal Rama Varma (Malayalam: ധർമ്മരാജാ കാർത്തിക തിരുനാൾ രാമവർമ്മ, 1724–17 Feb 1798) was the Maharajah of Travancore from 1758 until his death in 1798. He succeeded his uncle Marthanda Varma, who is credited with the title of "maker of modern Travancore". During his reign Dharma Raja not only retained all the territories his predecessor had gained but administered the kingdom with success. He was addressed as Dharma Raja on account of his strict adherence to Dharma Sastra, the principles of justice by providing asylum to thousands of Hindus and Christians fleeing Malabar during the religious and military onslaught of Tipu Sultan.
- Unfortunately, there are no memorials erected anywhere in Kodungallur, or Trichur, or Alwaye to honour Dharma Raja who gave shelter in his state to thousands of Hindus escaping from the Islamic brutalities of the fanatic Tipu Sultan; or Ayyappan Marthanda Pillai who was the architect of the historic Nedumkotta; or Raja Keshavadas under whose direct command a comparatively small army humbled and defeated the invading army of Tipu Sultan; or scores of valiant Hindu soldiers who laid down their lives to protect their country and faith.
- S.R. Goel in : Tipu Sultan - Villain or Hero (1993)
- Some time previous to the death of this Rajah, a female member of the Kolathnaud family was adopted as a Princess of Travancore, and Her Highness gave birth to a Prince in the Kollum year 899. This was the renowned Rama Rajah, generally called Dharma Rajah.
- A History of Travancore from the Earliest Times" by P.S. Menon. 1878. 
- It was in his time that the Travancore Rajah was known and generally styled " Rama Rajah" and " Dharma Rajah," which names are quite familiar to travellers who journey from Benares and other northern parts of India to Bamaswaram or Ramanad.
- A History of Travancore from the Earliest Times" by P.S. Menon. 1878.
- Don't you know I have achieved a great victory recently in Malabar and over four lakh Hindus were converted to Islam? I am determined to march against that cursed Raman Nair (Rajah of Travancore) very soon. Since I am overjoyed at the prospect of converting him and his subjects to Islam, I have happily abandoned the idea of going back to Srirangapatanam now.
- Tipu Sultan. In Tipu’s letter of 19 January 1790 to the Governor of Bekal, Budruz Zuman Khan (Badroos Saman Khan). quoted in K.M. Panicker, Bhasha Poshini, August 1923