An Ācārya (Ācārya) is the leader of an order of Jain ascetics (Munis), termed a sangh in the Jain tradition. Some of the famous achāryas are Bhadrabahu, Sthulibhadra, Kundakunda, Samantabhadra, Umaswati, Haribhadra, Hemachandra. In the Namokar Mantra, the five panch-paramsthis include Ācāryas, Upadhyayas and the ordinary Munis(Sadhus).

The lineage (line of ordination) of Ācāryas goes back to Lord Mahavira Swami. After the Ganadharas (immediate disciples of Lord Mahavira), there was a lineage of Kevalis (ending with Jambuswami), who were succeeded by Shruta-Kevalis. After the last Shruta-Kevali Bhadrabahu, two separate lineages of Ācāryas emerged, a Digambar lineage and a Shvetambara lineage. Several lineages of the Ācāryas exist in both sects. The lineages became Bhattaraka or Yati lineages when it became impossible for them to travel freely. Reforms during the British period restored the Ācārya lineages (Shvetambara Murtipujak Ācārya Vijayanandsuri in 1886 and Digambar Ācārya Shantisagar in 1922).

According to Ācārya Nemichandra (10th-century), Ācārya has thirty-six primary attributes (mūla guṇa) consisting in:

According to the Jain text, Dravyasamgraha,

Those who themselves practise the five-fold observances in regard to faith (darśanācāra), knowledge (jñānācāra), power (vīryācāra), conduct (cāritrācāra), and austerities (tapācāra), and guide disciples to follow these observances, are the Chief Preceptors (Ācāryas), worthy of meditation.” (52)

— Dravyasamgraha (52)

Chandanaji became the first Jain woman to receive the title of Ācārya in 1987.

The external austerities (bāhya tapas) are fasting (anaśana), reduced diet (avamaudarya), special restrictions for begging food (vrttiparisamkhyāna), giving up stimulating and delicious dishes (rasaparityāga), lonely habitation (viviktaśayyāsana), and mortification of the body (kāyakleśa).