Meir ben Isaac Katzenellenbogen (c. 1482 – 12 January 1565) (also, Meir of Padua, or Maharam Padua, Hebrew: מאיר בן יצחק קצנלנבויגן) was an Italian rabbi born in Katzenelnbogen.
Meïr ben Isaac, who was generally called after his native town, was the founder of the Katzenellenbogen family. After studying at Prague under the well-known casuist Jacob Pollak, he went to Padua and entered the yeshiva of Judah Minz, whose granddaughter, Hannah, he afterwards married. He succeeded his father-in-law, Abraham Minz, in the chief rabbinate of Padua, which office he held until his death on 12 January 1565 (epitaph below). He was the father of Samuel Judah Katzenellenbogen.
Meïr was also nominal rabbi of Venice, where he went several times a year, but he had his fixed residence at Padua. Meïr was considered by his contemporaries a great authority on Talmudic and rabbinical matters, and many rabbis consulted him, among them: Moses Alashkar, Obadiah Sforno, and his relative Moses Isserles (who addressed him as "rabbi of Venice"). It may be seen from his responsa (ninety in number, published by himself, with those of Judah Minz, under the title of She'elot u-Teshubot, Venice, 1553), as well as from those of Isserles, that he was disposed to be liberal in his decisions. Another indication of his leaning toward liberalism was his use in his responsa (Nos. 38, 49, 72) of the civil names of the months, a thing not done by other rabbis of his time.
Joseph ben Mordechai Gershon says (She'erit Yosef, No. 1) that Meïr, in one of his responsa, told him not to rely at that time on his opinion, because he could not verify his decision by the Talmud, all the copies of which had been burned. This burning is mentioned by David Gans (Ẓemaḥ Dawid, p. 56, Warsaw, 1890) and by Heilprin (Seder haDorot, i.245, ed. Maskileison) as having occurred in 1553 or 1554 under Pope Julius III, at the instigation of certain baptized Jews. Meïr states also (Responsa, No. 78) that in Candia the hafṭarah for Yom Kippur Minḥah was, with the exception of the first three verses, read in Greek (comp. Zunz, G.V. p. 413, note). In Responsum No. 86 he speaks of the plague that raged at Venice, but without indicating the year. Many of his responsa are to be found in the collection of Isserles. Meïr added to the edition of his responsa his father-in-law's Seder Giṭṭin wa-Ḥaliẓah, and a detailed index. He edited also Maimonides' Yad, with some commentaries, to which he added notes of his own (Venice, 1550; See Isserles).