Katherine Mayo (January 27, 1867 – October 9, 1940) was an American white nationalist, researcher and historian.
Mayo entered public life as a political writer advocating White Anglo-Saxon Protestant Nativism, opposition to non-white and Catholic immigration to the United States, and opposition to recently emancipated African slave laborers.
She became known for denouncing the Philippine Declaration of Independence on racialist and religious grounds, then went on to publish and promote her best-known work, Mother India (1927), wherein she opposed Indian Independence from British rule.
Her work was well received in British government circles and among American Anglophile racialists, but was criticized by others for notorious racism and Indophobia.