Gertrude Emily Johnson OBE (13 September 1894 – 28 March 1973) was an Australian coloratura soprano and founder of the National Theatre in Melbourne.
Johnson was born in 1894 at Prahran, Melbourne. She was the second child of George and Emily Johnson. George was a professor of music and both parents had been born in Victoria. Gertrude was educated at Presentation Convent, Windsor. On the advice of Nellie Melba, Johnson enrolled at the age of 17 in the University of Melbourne Conservatorium of Music as a student of Anne Williams. In 1915, she followed Williams to Melba's new women's singing school at the Albert Street Conservatorium, East Melbourne (later the Melba Memorial Conservatorium). Johnson was accepted into Melba's classes, and the relationship developed to the point where Melba gave Johnson her own personal cadenzas, a valuable professional asset. The director of Albert Street, Fritz Hart, had a particular interest in Mozartian opera and was responsible for introducing Johnson to what was to be the core of her repertoire.
Through introductions from Melba, Johnson begun touring outback Queensland and New South Wales in 1917 with Count Ercole Filippini's troupe, and in 1919 to Melbourne, Sydney, Adelaide and New Zealand with the Rigo Grand Opera Company. By 1921 she had sailed to London and started singing with the British National Opera Company. Soon she was singing roles such as Micaela in Carmen, Marguerite in Faust and the Princess in Holst's The Perfect Fool at Convent Garden. She also had an extensive recording career with Columbia Records. Miss Johnson sang on the initial BBC radio broadcast of live opera performances.