| William Johnston | |
| State: | Ohio |
| District: | 8th |
| Term Start: | March 4, 1863 |
| Term End: | March 3, 1865 |
| Preceded: | Samuel Shellabarger |
| Succeeded: | James Randolph Hubbell |
| Party: | Democratic |
| Birth Date: | 1819 |
| Birth Place: | Ireland, U.K. |
| Death Place: | Mansfield, Ohio, U.S. |
| Restingplace: | Mansfield Cemetery |
William Johnston (1819May 1, 1866) was an American lawyer and politician who served one term as a U.S. Representative from Ohio from 1863 to 1865.
Born on the island of Ireland (the entirety of which was then part of the U.K.) in 1819, Johnston immigrated to the United States and settled in Ohio.He attended the public schools.He studied law.He was admitted to the bar and practiced in Mansfield, Ohio, from 1859 to 1863.
Johnston was elected as a Democrat to the Thirty-eighth Congress (March 4, 1863 – March 3, 1865).He was an unsuccessful candidate for reelection in 1864 to the Thirty-ninth Congress.He resumed the practice of law.
He died in Mansfield, Ohio, May 1, 1866.He was interred in Mansfield Cemetery.