The Baraita of Rabbi Ishmael (Hebrew: ברייתא דרבי ישמעאל) is a baraita that explains the 13 rules of Rabbi Ishmael and their application, employing illustrations from the Torah.
The name is inaccurately given also to the first part of the Baraita, which only enumerates the 13 rules.
The thirteen rules were compiled by Rabbi Yishmael ben Elisha Nahmani ben Elisha for the elucidation of the Torah and making halakic deductions from it.
They are, strictly speaking, mere amplifications of the seven rules of Hillel the Elder, and are collected in the Baraita of Rabbi Ishmael, forming the introduction to the Sifra and reading as follows: Rules seven to eleven are formed by a subdivision of the fifth rule of Hillel; rule twelve corresponds to the seventh rule of Hillel, but is amplified in certain particulars; rule thirteen does not occur in Hillel, while, on the other hand, the sixth rule of Hillel is omitted by Ishmael.
With regard to the rules and their application in general, see also Talmudical hermeneutics.