KAPLAN, ALEXANDER SENDER BEN ZERAH HA-KOHEN (d. 1884), Lithuanian rabbi. Few biographical details are known about him. Kaplan served first as dayyan in Wilkomierz (Ukmerge), but was later appointed rabbi of Kupishki (Kupiskis) in the district of Ponevezh (Panevezys), where he served for 40 years. He is best known for his Shalmei Nedarim (1881), a comprehensive commentary on tractate *Nedarim. He regarded the compilation of a commentary on tractate Nedarim as of prime importance, because many errors had crept into it through the fault of the printers. Already in the previous generations this had resulted in haggahot being added to it by both Isaiah *Berlin-Pick and Samuel Straschun. Appended to the volume is Millu'im li-Shelamim containing a letter from Elijah David Rabinowitz-Teomim on a halakhic problem submitted to Kaplan, and his reply. Another responsum by Rabinowitz-Teomim to Kaplan is mentioned in the Shalmei Nedarim (p. 470). Kaplan's notes on the Talmud remain in manuscript.
D. Kamzon et al., Yahadut Lita, Temunot ve-Ḥiyyunim (1959), 95, 237; Yahadut Lita, 3 (1967), 305, 343.