The event is to take place Sept. 15 at The Plaza Hotel in Manhattan. CeCe Black, Anki Leeds and Howard Stringer will serve as gala co-chairs.
Lansbury has served as honorary chairman of the American Theatre Wing board of trustees since 2010.
"Angela Lansbury's contributions to the American theatre are incalculable and her advocacy on behalf of the wing unmatched," Heather Hitchens, executive director of the American Theatre Wing, said in a statement Tuesday. "We are incredibly honored to pay tribute to all that she has done to elevate the art form that we care so deeply about."