Charya tantra, Upa tantra, or Ubhaya tantra is a yana (literally "vehicle") of Esoteric Buddhism-though there is debate about whether it is considered to be buddhism, and as such is both a class of tantric literature and of praxis. The yana of Charya or ‘conduct’ tantra is given this name because it demonstrates a balanced emphasis on the outer ritual actions and ablutions of body and speech and the inner cultivation of intentionality and mindfulness. Hence, outer and inner conduct. The Charya tantra is enumerated as one of the three Outer Tantras in both the four-tantric-yanas classification scheme of the Sarma, or 'New Translation Schools' and the nine-yana classification of the Nyingma, 'Ancient Translation School'.
Guarisco & McLeod et al. (2005: p. 41) render this class into English as "Conduct".
One interpretation of 'Ubhaya' as the ‘tantra of both’ is demonstrated in that its literature and exponents hold the view of Yogatantra, whilst its conduct and activity is therein, as a general rule, is aligned with that of Kriyatantra and in function, forms a bridge between the two other Outer Tantras.
The Upa-yoga scriptures first appeared in 'Mount Jakang Chen' Tibetan: རི་བྱ་རྐང་ཅན, Wylie: ri bya rkang can (alternate names: Riwo Jakang, Mount Jizu) and the charnel ground of Cool Grove Tibetan: བསིལ་བའི་ཚལ, Wylie: bsil ba'i tshal. Cool Grove is also known as 'Śītavana' (Sanskrit).