| Walter Trumbull | |
| Birth Date: | c. 1846 |
| Birth Place: | Springfield, Illinois |
| Death Date: | October 25, 1891 |
| Occupation: | naturalist, writer |
Walter Trumbull (c. 1846 - 1891) was an American explorer and writer. He was a member of the Washburn–Langford–Doane Expedition in 1870 that explored the area of Wyoming that would eventually become Yellowstone National Park.
He was the son of United States Senator Lyman Trumbull.
He contributed to the Helena Rocky Mountain Gazette and the Overland Monthly.