Aleksander (Yiddish: אלעקסאנדער) is a Polish Hasidic dynasty originating from the city of Aleksandrow Lodzki, Poland, where it was founded by Grand Rabbi Yechiel Denciger (1828–1894).

Between the world wars, Hasidic Jews from all over flocked to the small village of Aleksander to spend the holiest days of the Jewish year in the presence of their spiritual leader, their rebbe, Rabbi Yitzchak Menachem Danciger (1879–1942).

After Shmuel Tsvi's death, the dynasty was continued by his son, Yitzchok Menachem Mendel Dancyger (1880–1943), whose accomplishments included the expansion of religious schools in Łódź and in Aleksander.

Nowadays, the community of chasidim of Aleksander exists mainly in Israel, but there are several synagogues (shtiblekh) in Boro Park, Monsey, Lakewood,[6] Cleveland, Antwerp, London, Zürich.

Rabbi Yehuda Moshe also spoke to survivors and collated their recollections of pre-war Aleksanderism in Meoran Shel Yisrael (Bnei Brak, 1971).

Over the tenure of his thirty two years as Rebbe, R' Avraham Menachem expanded the Aleksander community in four countries, and built a seven-story and yeshiva in the Slabodka neighborhood of Bnei Brak Israel.

His younger brother, R' Shneur Zalman, established a synagogue in Cleveland Ohio which he runs together with his family to serve the local non-hasidic community.