Bertha Vyver (11 June 1854 – 20 November 1941) was a caretaker for Scottish poet Charles Mackay and the companion of Marie Corelli. From 1875 until his death in 1889, Vyver kept house and nursed Mackay, later caring for her own mother prior to her death. Relieved of her nursing duties, Vyver remained with Corelli encouraging and facilitating her writing career. When Corelli died, Vyver became executor of her literary estate and wrote a biography of the author.