| State: | Wisconsin |
| State Assembly: | Wisconsin |
| District: | Green Lake - Waushara |
| Term Start: | January 9, 1957 |
| Term End: | January 6, 1969 |
| Predecessor: | William Belter |
| Successor: | Jon P. Wilcox |
| Office1: | Chairman of the Green Lake County Board of Supervisors |
| Term Start1: | 1944 |
| Term End1: | 1965 |
| Office2: | Chairman of the Marquette Town Board |
| Term Start2: | 1933 |
| Term End2: | 1964 |
| Party: | Republican |
| Birth Date: | 29 April 1900 |
| Birth Place: | Marquette, Wisconsin, U.S. |
| Death Place: | Fond du Lac, Wisconsin |
| Restingplace: | Markesan Memorial Cemetery Markesan, Wisconsin |
| Profession: | farmer, politician |
| Spouse: | Adelaide |
Franklin M. Jahnke (April 20, 1900 – July 3, 1979) was a member of the Wisconsin State Assembly, representing Green Lake and Waushara counties.
Jahnke was born on April 20, 1900, in the Town of Marquette, Wisconsin.[1] [2] He became a dairy farmer.[1] [3] He died at St. Agnes Hospital in Fond du Lac, Wisconsin, in 1979.[1] [4]
Jahnke was a member of the Assembly from 1957 to 1969.[1] Additionally, he was Chairman of the Town of Marquette from 1933 to 1964 and of the Green Lake County, Wisconsin Board from 1944 to 1965. He was a Republican.[1]