| János Grünn | |
| Order: | Minister of Finance of Hungary |
| Term Start: | 15 August 1919 |
| Term End: | 12 September 1919 |
| Predecessor: | Gyula Peidl |
| Successor: | Frigyes Korányi |
| Birth Date: | 1864 6, df=yes |
| Birth Place: | Besztercebánya, Kingdom of Hungary |
| Death Place: | Budapest, Kingdom of Hungary |
| Profession: | politician |
| Party: | Independent |
János Grünn (3 June 1864, Besztercebánya - 5 March 1932, Budapest) was a Hungarian politician, who served as Minister of Finance in 1919. After that he retired from politics.