James Vane — Sibyl's brother, a sailor who leaves for Australia. He is very protective of his sister, especially as their mother cares only for Dorian's money. Believing that Dorian means to harm Sybil, James hesitates to leave, and promises vengeance upon Dorian if any harm befalls her. After Sibyl's suicide, James becomes obsessed with killing Dorian, and stalks him, but a hunter accidentally kills James. The brother's pursuit of vengeance upon the lover (Dorian Gray), for the death of the sister (Sybil) parallels that of Laertes vengeance against Prince Hamlet.
Alan Campbell — chemist and one-time friend of Dorian who ended their friendship when Dorian's libertine reputation devalued such a friendship. Dorian blackmails Alan into destroying the body of the murdered Basil Hallward; Campbell later shoots himself dead.
Lord Fermor — Lord Henry's uncle, who tells his nephew, Lord Henry Wotton, about the family lineage of Dorian Gray.
Victoria, Lady Wotton — Lord Henry's wife, whom he treats disdainfully; she divorces him.