Patricia Marjorie Ralph (5 April 1920 – 23 March 1995) was a New Zealand marine biologist and university lecturer.

She was born in Wellington, New Zealand in 1920. She graduated from Victoria University College with a Bachelor of Science in 1941 and a Master of Science two years later. She remained as a demonstrator at Victoria College and became a junior lecturer and then received a tenured position in 1949. Her work in marine biology received worldwide attention and she was awarded a Doctor of Science in 1962, the first woman at Victoria to be recognised with that degree. Two species of coral, Sphenotrochus ralphae and Caryophyllia ralphae, were named for her.^[1]

Ralph died at Paraparaumu in 1995,^[1] and her ashes were buried in Bolton Street Memorial Park, Wellington.^[2][3]