| Harold Gerard Mosier | |
| State: | Ohio |
| District: | At-large |
| Term Start: | January 3, 1937 |
| Term End: | January 3, 1939 |
| Preceded: | Daniel S. Earhart Stephen M. Young |
| Alongside: | John McSweeney |
| Order2: | 45th |
| Office2: | Lieutenant Governor of Ohio |
| Governor2: | Martin L. Davey |
| Term Start2: | January 14, 1935 |
| Term End2: | January 11, 1937 |
| Preceded2: | Charles W. Sawyer |
| Succeeded2: | Paul P. Yoder |
| Office3: | Member of the Ohio Senate |
| Term3: | 1933–1935 |
| Party: | Democratic |
| Birth Date: | 24 July 1889 |
| Birth Place: | Cincinnati, Ohio |
| Death Place: | Washington, D.C. |
| Restingplace: | Fort Lincoln Cemetery |
| Spouse: | Grace Hoyt Jones |
| Alma Mater: | Dartmouth College Harvard Law School |
Harold Gerard Mosier (July 24, 1889 – August 7, 1971) was an American lawyer and politician who served as a U.S. Representative from Ohio for one term from 1937 to 1939. He was also the 45th lieutenant governor of Ohio from 1935 to 1937.
Mosier was born in Cincinnati, Ohio. He attended East High School in Cleveland, Ohio. He was graduated from Dartmouth College, Hanover, New Hampshire, in 1912 and from the law department of Harvard University in 1915. He was admitted to the bar in 1916 and commenced practice in Cleveland.
Mosier married Grace Hoyt Jones of Columbus, Ohio, April 20, 1918.[1]
He served as a member of the Ohio Senate 1933-1935 and was the lieutenant governor of Ohio 1935-1937.
Mosier was elected as a Democrat to the Seventy-fifth Congress (January 3, 1937 – January 3, 1939). He sat on the Dies Committee.He was an unsuccessful candidate for renomination in 1938. He resumed the practice of law in Cleveland, Baltimore, and Washington, D.C. He was Counsel to Glenn L. Martin Co. and the Aircraft Industries Association. He retired in 1961.
He resided in Washington, D.C., until his death there on August 7, 1971. He was interred in Fort Lincoln Cemetery.