Shìyǒu 世友 (Skt. Vasumitra “Friend of the Vasus”; also transliterated 婆蘇蜜多羅 Pósuōmìduōluó and 和須蜜 Héxūmì; DILA Authority A000211) was a Sarvāstivāda Abhidharma master of uncertain date, traditionally placed in the first to second centuries CE. He is credited with the Prakaraṇa-pāda (品類足論, KR6l0007) and the Dhātu-kāya-pāda (界身足論, KR6l0005) among the six canonical Abhidharma feet. A separate work, the Zhòngshì fēn Āpítán lùn (眾事分阿毘曇論, KR6l0006), is also attributed to a Vasumitra.
The name Vasumitra is shared by several Sarvāstivāda masters. The most prominent is the compiler or president of the Kaśmīra Abhidharma council under Kaniṣka, credited with presiding over the composition of the Mahāvibhāṣā (KR6l0010) and with authoring the Yì-bù zōnglún lùn 異部宗輪論 (T2031, a survey of sectarian differences). The relationship between this council-era Vasumitra and the Vasumitra of the six-feet texts is disputed in modern scholarship; they may be the same person, or the name may have been applied to different masters.
Works in the Kanripo corpus attributed to 世友: KR6l0005 阿毘達磨界身足論 (T1540); KR6l0006 眾事分阿毘曇論 (T1541); KR6l0007 阿毘達磨品類足論 (T1542); KR6r0007 異部宗輪論 (T2031, the locus classicus for the Buddhist sectarian schism).