Katharine Waldo Douglas, CBE, (1870 – April 7, 1939) was an American novelist and translator. She was born in New York City, the daughter of Henry Livingston Douglas and Hortense Pauline Armstrong. Katharine married Francis Hunter in 1894. She later married the artist Romilly Fedden. The writer Robin Fedden was their son. They lived in Chantemesle, France; Robin Fedden later wrote a well-regarded memoir titled Chantemesle.
She wrote several books in the early 20th century, among them The Sign (1912), The Spare Room (1913), Shifting Sands (1914), The Rock (1915), The Basque Country (1921), and The Peacock's Tail (1925). She also published Manor Life in Old France; From the Journal of Sire de Gouberville in 1933.
She was actively involved in relief work in London during World War I and was decorated by King George V for her efforts.
She died of injuries received in the crash of the Sud Express near Tolosa on March 29, 1939. Romilly Fedden died in the same crash.