William Otis Crosby (January 14, 1850, Decatur, Byrd Township, Brown County, Ohio - 31 December 1925, Boston) - American geologist and engineer, Professor of the Massachusetts Institute of Technology (1906), a member of the American Academy of Arts and Sciences (1881).

Since 1875, while still a student, he was an assistant in geology and mineralogy in the Boston Society of Natural History, where he worked under the guidance of the famous paleontologist Alpheus Hyatt.

[2] In 1881 he was elected a member of the American Academy of Arts and Sciences in Cambridge, Massachusetts.

After the termination of teaching activity and until the end of his life, he worked as an expert consultant on the construction of engineering structures.

The research covered such areas as mineralogy, igneous rocks, glaciology, physical geography, metamorphism, economic geology, fracture disturbance and tectonics, coral reefs, engineering geology and groundwater.