Manihot walkerae, commonly known as Walker's manihot, is a species of flowering plant in the spurge family, Euphorbiaceae, that is native to the Lower Rio Grande Valley of Texas in the United States and Tamaulipas in Mexico. The specific name honours amateur botanist Thelma Ratcliff (Mrs. E. J.) Walker, who discovered the type specimen near Mission and La Joya, Texas in 1942.