The Mefarsh (“explainer”) is an anonymous commentary on the Talmudic tractate of Tamid (until ch. 5), on which there is no extant commentary by Rashi.

Some have attributed the commentary to the Tosafist Rabbi Yitzchak Ben Baruch. Others have attributed it to Rabbi Shemayah, a preeminent student of Rashi.

However, others point out, especially in light of the discovery of Rabbi Shemayah’s own commentary to Tamid and Midot, that these assertions are erroneous.

Rabbi Bezalel Ashkenazi (16th-century author of Shitah Mekubetzet) points out that a good portion of this commentary is culled from Rashi's commentary on tractate Yoma.