Thomas Taylor (1820–1910) was a Scottish-American plant pathologist and microscopist.

He was among the first to publish works on microscopic plant pathology with the USDA.

He immigrated to the United States at the invitation of Abraham Lincoln in 1851.

He was often criticized for his lack of professional training, and his work was discredited and buried by his colleagues.

However, his research into fungal diseases of fruit was later praised.