Kathleen Mary Drew-Baker (6 November 1901 – 14 September 1957) was a British phycologist, known for her research on the edible seaweed Porphyra laciniata (nori), which led to a breakthrough for commercial cultivation.

Kathleen Drew-Baker’s scientific legacy is revered in Japan, where she has been named Mother of the Sea. Her work is celebrated each year on 14 April. A monument to her was erected in 1963 at the Sumiyoshi shrine in Uto, Kumamoto, Japan.