Mathilde von Keller (1853–1945) was a German courtier and memoir writer.
Mathilde was daughter of Count Gustav von Keller (1805-1897) and his second wife Mathilde von Grolman (1813-1900).
She served as lady-in-waiting to Empress Augusta Victoria of Schleswig-Holstein from 1881. She was her fourth cousin, once removed as both have descended from Count Johann Christian I of Solms-Baruth (1670-1726) and his wife Countess Helena Constantia Henckel von Donnersmarck (1677-1753). Alongside Countess Therese von Brockdorff (1846–1924) and Countess Claire von Gersdorff (1858-1927), she was a favorite of the Empress and together they were referred to as "The three Hallelujah Aunts". Her memoirs of her life at court have been published.