William Henry Whitmore (September 6, 1836 – June 14, 1900) was a Boston businessman, politician and genealogist.

William Henry Whitmore was born in Dorchester, Massachusetts on September 6, 1836.

His "Ancestral Tablets" (Boston, 1868) was an invention for genealogists, being a set of pages cut and arranged to admit the insertion of a pedigree in a condensed form.

Whitmore was an editor of the New England Historical and Genealogical Register, in which many of his papers first appeared, and The Heraldic Journal, which he established in 1863.

Whitmore contributed to various magazines, native and foreign, and was the author of many genealogies, the most important of which are the families of Temple, Lane, Norton, Winthrop, Hutchinson, Usher, Ayres, Payne, Whitmore, Lee, Dalton, and Wilcox.