SS Gwendolen (sometimes misspelled Guendolen and Gwendolyn) was a British steamship on Lake Nyasa that fought in the first naval action of World War I against the German steamship Hermann von Wissman which it caught on a slipway at Liuli. The 350 ton vessel was launched at Fort Johnston in 1899, and named after Lady Gwendolen Cecil, the then 29 year old unmarried daughter of the Marquess of Salisbury. In 1907 the Gwendolen was the largest of three vessels formerly used as gunboats, the others being the SS Chauncy Maples and the Queen Victoria, with four civilian steamers on the lake.