Big Lonely Doug is a large Coast Douglas-fir (Pseudotsuga menziesii) tree located in the Gordon River Valley, 10km north of Port Renfrew on Vancouver Island, British Columbia, Canada.

It is the second largest Douglas-fir tree in Canada after the Red Creek Fir in nearby San Juan Valley.

[1] In 2011, logger Dennis Cronin discovered the enormous tree while surveying a patch of forest that was to be logged for timber.

In 2014, photographer and activist T.J. Watt happened upon the tree and named it "Big Lonely Doug", a play on the tree's species name and its relative isolation amid the clearcut.

The tree has since become a symbol of nature conservation in Canada,[2][3] and was featured in the 2018 book Big Lonely Doug: The Story of One of Canada's Last Great Trees by journalist Harley Rustad.