Samuel Waldo (August 7, 1696 – May 23, 1759) was an American merchant, land speculator, army officer and politician in the Province of Massachusetts Bay.

A one-time business partner of Colonel Thomas Westbrook, Waldo acquired a large tract of land between the Penobscot and Muscongus Rivers in what is now Maine where he settled Irish and German immigrants and purchased several slaves.

Waldo died of apoplexy near present-day Bangor, Maine in 1759 while participating in a military expedition with Governor Thomas Pownall.

[5] His son-in-law Thomas Flucker was royal secretary of Massachusetts and later Provincial Governor.

The Knox family built the impressive Montpelier on Waldo's tract of land in Thomaston, Maine.