Ohio's 4th senatorial district has been based in southwestern Ohio and now consists of almost all of Butler County. It encompasses Ohio House of Representatives districts 51, 52 and 53. It has a Cook PVI of R+13. Its current Ohio Senator is Republican George Lang.
| Senator | Party | Term | Notes |
|---|---|---|---|
| Walter E. Powell | Republican | January 3, 1967 – January 2, 1971 | Powell was elected to the United States Congress in 1970. |
| Donald E. "Buz" Lukens | January 3, 1971 – January 2, 1987 | Lukens was elected to the United States Congress in 1986. | |
| Barry Levey | January 4, 1987 – June 30, 1995 | Levey retired prior to the expiration of his term.[1] | |
| Scott Nein | July 11, 1995 – December 31, 2004 | Nein was term limited. | |
| Gary Cates | January 3, 2005 – May 22, 2011 | Cates resigned to become an administrator for the Ohio Board of Regents. | |
| Bill Coley | May 23, 2011 – December 31, 2020 | Coley was term limited. | |
| George Lang | January 4, 2021 – present | Incumbent. |