Naiyayika (Sanskrit: नैयायिक , Romanised: Naiyāyika) is referred to a follower of the Nyāya school of the Indian philosophy founded by the Vedic sage Akshapada Gautama.

[1][2][3][4] The main occupations of the Naiyayikas are the investigations of the truth and acquiring correct knowledge through the process of logical reasonings.

These sixteen categories are pramāṇa, prameya, saṃśaya, prayojana, dṛṣṭānta, siddhānta, avayava, tarka, nirnaya, vāda, jalpa, vitaṇḍā, hetvābhāsa, chhala, jāti, nigrahasthāna.

The history of the tradition of Naiyayikas span nearly three thousand years back from the present time.

The history of Naiyayikas started from the time when the Nyaya Sutras was founded by the Vedic sage Akshapada Gautama in Mithila.

He wrote a commentary on the text Nyaya Sutras of Akshapada Gautama to answer the questions of Buddhists.

[17][18] Bhasarvajna was another eminent Naiyayika from the Kashmir region of Indian subcontinent in the era of 10th century CE.

[19] During the period of 10th - 11th century CE, Udayanacharya emerged as a prominent Naiyayika in Mithila who reconciled the views of the two independent schools of thought Nyaya and Vaisheshika of the Indian philosophy and led the foundation of the Navya Nyaya school of thought.

He attempted to devise a rational theology to counter the attack on the existence of God at the hands of Buddhist philosophers such as Dharmakīrti, Jñānaśrī and against the Chārvaka school of materialism.

[20][21] Apart from the text Nyayakusumanjali, he also wrote Nyāyavārttikatātparyapariśuddhi, Nyāyapariśiṣṭa, Probodhasiddhi (Bodhasiddhi), Ātmatattvaviveka, Kiraṇāvalī and Lakṣaṇāvalī.