Helen Lehman Buttenwieser (October 8, 1905 – November 22, 1989) was a 20th-century American lawyer, philanthropist, and later-life legal counselor of Alger Hiss.
Helen Lehman was born on October 8, 1905, to the Lehman family of New York. Her parents were Arthur Lehman (son of Mayer Lehman, founder of the New York Cotton Exchange and partner in Lehman Brothers Bank) and Adele Lewisohn (daughter of Adolph Lewisohn).
She attended Horace Mann School. In 1923, she graduated from Connecticut College for Women. During the period 1927–1933, she attended the New York School of Social Work and took courses at Columbia University. In 1936, she graduated from New York University Law School.
From 1927 to 1932, she became a social worker. She worked for the Wardell Commission on Social Welfare and Foster Home Bureau of Hebrew Sheltering Guardian Society. From 1929 to 1945, she served on the board of the Madison Settlement House. From 1930 to 1935, she served as a commissioner on the New York City Board of Child Welfare.
In 1936, she became the first woman to work at the law firm of Cravath, Swaine & Moore but left after a year because of the impending birth of one of her children. In 1937, she became one of the first women admitted to the New York City Bar Association. Also in 1937, she began a half-century association with the Legal Aid Society (first woman chairman 1979–1983). In 1942, she became a 20-year trustee of the Dalton School. In 1947 (to 1950), she became first chairwoman of a standing committee of the Bar Association of the City of New York. In 1949, she became the first female bank director, as trustee of the Title Guarantee and Trust Company. Also, from 1949 to 1950, she was a member of the civil rights committee of the New York State Bar Association. From 1949 through 1980, she served as a trustee of Connecticut College.