
Menzel was born Idina Kim Mentzel in New York. She grew up in Syosset. Her mother, Helene, is a therapist, and her father, Stuart Mentzel, worked as a pajama salesman. She has a younger sister named Cara. Menzel’s family is Jewish; her grandparents emigrated from Russia and elsewhere in Eastern Europe.
When Menzel was 15 years old, her parents divorced and she began working as a wedding and bar mitzvah singer, a job which she continued throughout her time at New York University’s Tisch School of the Arts. Menzel, however, did not have a bat mitzvah after she quit Hebrew school. Menzel attended Syosset High School.