John Cameron Semple (born 1947) is a Canadian botanist and professor emeritus and adjunct professor at the University of Waterloo. He received a Bachelor of Science in 1969 from Tufts University, and a Master of Arts and Doctor of Philosophy from Washington University, St. Louis, in 1971 and 1972, respectively. He is known for his work on members of the tribe Astereae, particularly the multiple aster genera, goldenasters, and goldenrods. He maintains the University of Waterloo Astereae Lab website. Semple's wife is named Brenda, and he named a new species Solidago brendiae in honor of her.