Sifra (Aramaic: סִפְרָא) is the Halakic midrash to Leviticus. It is frequently quoted in the Talmud, and the study of it followed that of the Mishnah, as appears from Tanḥuma, quoted in Or Zarua, i. 7b. Like Leviticus itself, the midrash is occasionally called "Torat Kohanim" (Ḳid. 33a; Sanh. 103b; Cant. R. vi. 8), and in two passages also "Sifra debe Rab" (Ber. 11b, 18b). According to Leḳaḥ Ṭob (section צו), this latter title was applied originally to the third book of the Pentateuch because Leviticus was the first book studied in the elementary school, and it was subsequently extended to the midrash; but this explanation is contradicted by analogous expressions such as "Sifre debe Rab" and, in a broader sense, "ketubot debe Rab" (Yer. Ket. 26c) and "teḳi'ata debe Rab" (Yer. Ab. Zarah 39c).
It is true, Maimonides, in the introduction to his Yad ha-Ḥazaḳah, and others, quoted by Friedmann, in the introduction to his edition of the Mekilta (p. xxvi., Vienna, 1870), have declared that the title "Sifra debe Rab" indicates Rab as the author of the Sifra; and this opinion I.H. Weiss, in the introduction to his Sifra edition (p. iv.), attempts to support. His proofs are not conclusive, however; neither, it must be confessed, are the opposing arguments of Friedmann (l.c. pp. xvi. et seq.), who tries to show that the expression "Sifra debe Rab" does not refer to the midrash under discussion.