Lieutenant-Colonel Arthur Trefusis Heneage Williams MP (June 13, 1837 – July 4, 1885) was a Canadian businessman, farmer and political figure.

Born at Penryn Park, Port Hope in Upper Canada in 1837, a member of the Williams family of Caerhays and Burncoose.

He was the eldest son of John Tucker Williams and his wife Sarah, daughter of Judge Thomas Ward (1770–1861) of Port Hope.

The Dictionary of Canadian Biography writes, Colonel Williams was the only nationally known figure to die in the northwest campaign and his body was brought home in state.

To Charles Arkoll Boulton, a contemporary, Williams "represented what might be termed Young Canada"; to posterity, he reflects a model of the patriotic landed gentleman, using his wealth and position for dignified public service, accepting payment in the currency of honour and prestige.