Mary Lois Walker Morris (1835-1919) was an English immigrant, poetess, and plural wife in Salt Lake City, Utah.

Mary Morris was born on May 14, 1835 in Leek, Staffordshire, England to parents Mary Godwin and William Gibson Walker. She grew up in the Wesleyan Methodist church. Around the age of 9 she attended Mormon sermons with her father, decided to join the Church, and was baptized in approximately 1844. On February 18, 1850, she emmigrated with her family from England to America. They lived and worked in St. Louis, Missouri, to raise money to travel West to Salt Lake City, Utah; Morris worked as a housekeeper and babysitter and later worked in a female seminary.

She married John Thomas Morris in September 1852 and they had one son. The marriage ended tragically in 1855 with the death of their son followed by John's demise from tuberculosis in Cedar City, Utah. On his deathbed, John, invoking the principle of levirate marriage, asked his older brother Elias to marry Mary Lois and rear up children to him. Elias and Mary Lois had eight children, with five surviving to adulthood. One of their sons, George Q. Morris, became an apostle for the Church under President David O. McKay.

In 1884, Morris was called to be the Primary president for her ward in 1884; she had this calling for twelve years. In approximately 1896, she was called as a counselor to the Salt Lake Stake Primary Board. She was interested in writing and in 1902 was chosen as a member of the program committee for The Reaper's Club, a group founded by Emmeline B. Wells dedicated to reading and writing. In 1902, Mary accompanied her daughter to live in Colonia Juarez, Mexico where Latter-day Saints could practice plural marriage without persecution. In Mexico, Mary learned Spanish, took religion classes, and began writing poetry and memoirs. However, they struggled in Mexico and returned to Utah in May 1905.

Mary Lois Walker Morris died on November 29, 1919 in Salt Lake City, Utah.