| Johann Kaspar Freiherr von Seiller | |
| Order: | Mayor of Vienna |
| Term Start: | 1851 |
| Term End: | 1861 |
| Predecessor: | Ignaz Czapka |
| Successor: | Andreas Zelinka |
| Birth Date: | 20 October 1802 |
| Birth Place: | Maribor, Styria, Habsburg monarchy (present-day, Slovenia) |
| Death Place: | Vienna, Austria-Hungary |
| Spouse: | Maria Weigl |
| Children: | Josef von Seiller, Aloys von Seiller, Anton von Seiller, Maria Walpurga von Schwaiger, Viktor von Seiller, Maximilian von Seiller. |
| Profession: | Lawyer, Judge, Politician |
| Education: | Doctor of Law (University of Vienna) |
Johann Kaspar Freiherr von Seiller was the first freely elected mayor of Vienna.[1]