Ammi, Aimi, Immi (Hebrew: רבי אמי) is the name of several Jewish Talmudists, known as amoraim, who lived in the Land of Israel and Babylonia. In the Babylonian Talmud the first form only is used; in the Jerusalem Talmud all three forms appear, Immi predominating, and sometimes R. Ammi is contracted into "Rabmi" or "Rabbammi" (Yer. Ab. Zarah, v. 45a, b).
The most distinguished "Ammi" is an amora of the third generation (3rd century). His native country is not named, but it is generally assumed to be Babylonia. It seems probable that the lifelong friendship existing between R. Ammi and R. Assi had its origin in ties of blood. R. Assi is identical with R. Assi (Jose) b. Nathan, and R. Ammi's full name, as given by himself, is Ammi ben Nathan (Giṭ. 44a); both of them, moreover, were of priestly descent (Meg. 22a, Ḥul. 107b), so that they seem to have been the sons of the same father; and as R. Assi is a native Babylonian, there is reason for assuming R. Ammi's Babylonian nativity.
In his early age Ammi attended the college at Caesarea, presided over by R. Hoshaiah I (Yer. Shab. iii. 5d), and later he went to Tiberias and became the disciple of R. Johanan, at whose death he voluntarily observed the ritual period of mourning prescribed on the death of nearest relatives only (M. Ḳ. 25b). When he once heard that his Babylonian contemporary, R. Nachman, had expressed himself disrespectfully of a misapplied opinion of R. Johanan, he indignantly exclaimed, "Does NaḦman think that because he is the son-in-law of the exilarch, he may speak disparagingly of R. Johanan's opinions?" (Ḥul. 124a). In Tiberias he became the center of a large circle of learned friends, among whom were R. Abbahu, R. Ḥanina (Ḥinena) b. Pappi, R. Isaac, and R. Samuel b. NaḦmani (M. Ḳ. 17a, 20a; Yeb. 48b), but the closest and most enduring friendship existed between him and R. Hiyya bar Abba and R. Assi (Berachot 16a, Yer. Pes. iii. 30b), both of whom were Babylonian immigrants.