Drawing-room at Hunstanton

Gerald's mother arrives at the end of an argument between Hester and the upper class women. Lord Illingworth enters shortly after, and Gerald uses the opportunity to introduce him to Mrs. Arbuthnot. The three share an uncomfortable exchange, as Mrs. Arbuthnot (to Gerald's dismay) can only partially expresses her disapproval of Illingworth's offer. Lord Illingworth excuses himself, and Lady Hunstanton calls everyone into her music-room soon after. Illingworth, however, requests that he remain behind to speak with Mrs. Arbuthnot.

What follows is the reveal that Gerald is the illegitimate child of Mrs. Arbuthnot and Lord Illingworth, once known as George Harford. Years ago, Mrs. Arbuthnot and George Harford conceived a child, yet Harford refused to marry Arbuthnot. Harford had offered to provide financial security through is mother, but according to Mrs. Arbuthnot, it was his refusal to marry that forced her to leave him and live an arduous life as a scandalous single mother. Mrs. Arbuthnot retains a strong bitterness toward Illingworth, yet also begs him to leave her son alone, expressing that after twenty years of being a mother, Gerald is all she has. She refuses to allow Gerald to stay with his father, but Illingworth questions how she will force Gerald to do what she wants. He tells Mrs. Arbuthnot that Gerald should be able to choose his own future. Gerald then enters, and Lord Illingworth assures him and his mother that Gerald has the highest qualities that the man had hoped for in a secretary. Illingworth demands any other reason for Mrs. Arbuthnot to protest against Gerald's opportunity. Unwilling to reveal her son's true heritage, Mrs. Arbuthnot says that she has no other reason.

Act III