The genre ‘bāhirasattha’ (S. bāhyaśāstra) is found fairly often in Sri Lankan works as an ancillary to ‘tepitaka‘, religious scriptures . For instance, in the 12th century Hatthavanagallavihāravaṃsa, a youth (kumāraka) is made to learn the scriptures (tepitaka) and ‘bāhirasattha’. Also in his Dambulla inscription, Nissaṅka Malla states that he encouraged the study of the scriptures and ‘bāhirasattha’. GUNAWARDANA translates the latter as ‘extraneous śāstras’ and understands the term ‘bāhira’ as simply referring to non-canonical literature. It is possible, however, that this term also had ideological connotations. For instance, Buddhaghosa uses a similar expression ‘bāhiraka’ in the Samantāpasādikā (Sp) to refer to non-Theravādin literature:
One should check that a sutta conforms to the orthodox sutta (suttānuloma). If it conforms and agrees [with the orthodox sutta], and if one perceives that the received canonical text was compiled at the third council, it should be accepted. [However,] if one does not perceive this, [and] if it does not conform and agree [with the orthodox sutta], it is a sutta of Outsiders (bāhirakasutta), or it is a poem or it is something else. One should not accept a contemptible sutta that has been received from either the Secret Vessantara, the Secret vinaya or the Vedalla [piṭaka]. One should determine that [the sutta] is only an orthodox sutta. 
In this discussion, the term ‘bāhirakasutta’ clearly refers to the literature of other Buddhist sects. This is confirmed by Sāriputta’s gloss of the term in his commentary (Sd-ṭ), where he states that ‘the [term] bāhirakasutta’ [refers to] suttas of the members of the Mahāsaṅghikanikāya, such as the Secret Vessantara, that were not compiled at the third council.’ Therefore, the use of the term ‘bāhirasattha’ may not simply refer to non-canonical śāstras but could also refer to śāstras of non-Theravādin origin. In this regard, the frequent use of the term ‘bāhirasattha’ in these later Pali works may be symptomatic of an increasing engagement of the Lankan sangha with other non-Theravādin sects at the turn of the second millennium .
 Att 2.10,2.
 GUNAWARDANA 1979: 160-161.
 Sd Ee 1.232.
suttaṃ suttānulome otāretabbaṃ. sace otarati sameti, tisso saṅgītiyo ārūḷhaṃ pāḷiāgataṃ paññāyati, gahetabbaṃ. no ce tathā paññāyati na otarati na sameti, bāhirakasuttaṃ vā hoti siloko vā aññaṃ vā. gārayhasuttaṃ guḷhavessantaraguḷhavinayavedallādīnaṃ aññatarato āgataṃ, na gahetabbaṃ. suttānulomasmiṃ yeva ṭhātabbaṃ.
 Sd-ṭ Be 2.47.
bāhirakasuttan ti tisso saṅgītiyo anāruḷhaguḷhavessantarādīni mahāsaṅghikanikāyavāsīnaṃ suttāni.