Jyotirishwar Thakur or Kaviśekharācārya Jyotirīśvara Ṭhākura (1290–1350) was a Maithil poet and an early Maithili and Sanskrit writer, known for the Varṇa Ratnākara, his encyclopedic work in Maithili.
His was son of Rāmeśvara and grandson of Dhīreśvara. He was the court poet of Nepalese King Harisimhadeva of Karnata dynasty in Janakpur of Mithila (r. 1300–1324).
His most significant work in Maithili, the Varṇa Ratnākara (1324) is an encyclopedic work in prose. This work contains descriptions of various subjects and situations. This work provides valuable information about the life and culture of medieval India. The text is divided into seven Kallolas (waves): Nagara Varṇana, Nāyikā Varṇana, Asthāna Varṇana, Ṛtu Varṇana, Prayāṇa Varṇana, Bhaṭṭādi Varṇana and Śmaśāna Varṇana. An incomplete list of 84 Siddhas is found in the text, which consists only 76 names. A manuscript of this text is preserved in the Asiatic Society, Kolkata (ms. no 4834 of Asiatic Society of Bengal).
His major Sanskrit play, the Dhūrta Samāgama (The Meeting of the Knaves) (1320) is a two act Prahasana (comedy). The play relates the contest between a religious mendicant Viśvanagara and his disciple Durācāra over a lovely courtesan Anaṅgasenā whom the Brahmin arbitrator Asajjātimiśra keeps for himself. Superior characters in this drama speak in Sanskrit, inferior characters speak in Prakrit and the songs are in Maithili.
- Majumdar 1960, p. 515. "The Varṇa Ratnākara of Jyotirīśvara Ṭhākura ... was written about 1325. This is a work of set descriptions of various subjects and situations, to supply ready-made cliché passages to story-tellers ... [it] is important, not only because it gives us specimens of pure Maithilī prose ... but also because it is a store-house of information, conveyed through words, about the life and culture of early Medieval India in all their aspects."
- Shastri, Haraprasad (ed.) (2006). Hajar Bacharer Purano Bangala Bhasay Bauddhagan O Doha (in Bengali) Kolkata: Bangiya sahitya Parishad, pp.35-6
- Majumdar 1960, p. 471. "[Describing erotic and farcical Sanskrit literature:] Dhūrtasamāgama is a Prahasana by Jyotirīśvara Ṭhākura ... c. 1320 ... The play relates the contest between a religious mendicant Viśvanagara and his pupil Durāchāra over a lovely courtesan Anaṅgasenā , whom the Brāhmaṇa arbitrator Asajjāti keeps for himself."
- Jha, V.N. (2003). Sanskrit Writings in Independent India, New Delhi: Sahitya Akademi, ISBN 81-260-1812-7, p.179
- Majumdar 1960, p. 488. "The Pañchasāyaka by Jyotirīśvara Ṭhākura ... epitomises in five parts all that is said in standard works on Kāmaśāstra."
- Chatterji S.K. and S.K. Mishra (ed.) (1940). Varṇa Ratnākara of Jyotirīśvara, Bibliotheca Indica, Calcutta: The Asiatic Society.
- Majumdar, Ramesh Chandra; Pusalker, A. D.; Majumdar, A. K., eds. (1960). The History and Culture of the Indian People. VI: The Delhi Sultanate. Bombay: Bharatiya Vidya Bhavan.