Henrietta Szold (/zoʊld/ ZOHLD, Hungarian: [ˈsold]; December 21, 1860 – February 13, 1945) was an American-born Jewish Zionist leader and founder of Hadassah, the Women's Zionist Organization of America. In 1942, she co-founded Ihud, a political party in Mandatory Palestine dedicated to a binational solution. An obituary in the New York Times described her as "the most brilliant woman in America."

Henrietta Szold was born in Baltimore, Maryland, December 21, 1860. She was the daughter of Rabbi Benjamin Szold of Hungarian birth, who was the spiritual leader of Baltimore's Temple Oheb Shalom. She was the eldest of eight daughters, and her younger sister Adele Szold-Seltzer was the translator of the first American edition of Maya the Bee.

In 1877, Henrietta Szold graduated from Western High School. For fifteen years she taught at Miss Adam's School and Oheb Shalom religious school, and gave Bible and history courses for adults. Highly educated in Jewish studies, she edited Professor Marcus Jastrow's Talmudic Dictionary. To further her own education, she attended public lectures at Johns Hopkins University and the Peabody Institute.

In 1902, Szold took classes in advanced Jewish studies at the Jewish Theological Seminary of America. However, its rabbinic school was restricted to males. Szold begged the school's president, Solomon Schechter, to allow her to study; he did only with the provision that she not seek ordination. Szold did well at the seminary, earning the respect of other students and faculty alike.

Szold never married and never had children of her own. While she was in her forties, she had an unrequited relationship with Talmudic scholar Rabbi Louis Ginzberg. He was fifteen years her junior, and he returned her feelings only platonically. After their relationship ended, she expressed her sadness: "Today it is four weeks since my only real happiness was killed." Years afterward, she said: "I would exchange everything for one child of my own."

Szold was the oldest of eight daughters and had no brothers. In Orthodox Judaism, it was not the norm for women to recite the Mourners' Kaddish. In 1916, Szold's mother died, and a friend, Hayim Peretz, offered to say Kaddish for her. In a letter, she thanked Peretz for his concern but said she would do it herself.

"I know well, and appreciate what you say about the Jewish custom; and Jewish custom is very dear and sacred to me. And yet I cannot ask you to say Kaddish after my mother. The Kaddish means to me that the survivor publicly and markedly manifests his wish and intention to assume the relation to the Jewish community, which his parent had, and that so the chain of tradition remains unbroken from generation to generation, each adding its own link. You can do that for the generations of your family, I must do that for the generations of my family."

Szold's answer to Peretz is cited by "Women and the Mourners' Kaddish," a responsum written by Conservative Rabbi David Golinkin. This responsum, adopted unanimously by Conservative Judaism's Va'ad Halakhah (Law Committee) of the Rabbinical Assembly of Israel, permits women to recite the Mourners' Kaddish in public when a minyan is present. Szold was religiously traditional, but advocated a larger role for women in Rabbinic Judaism.