| Karlstein an der Thaya | |
| Pushpin Map: | Austria |
| Pushpin Mapsize: | 270 |
| Pushpin Map Caption: | Location within Austria |
| Coordinates: | 48.8833°N 15.4°W |
| Subdivision Type: | Country |
| Subdivision Name: | Austria |
| Subdivision Type1: | State |
| Subdivision Name1: | Lower Austria |
| Subdivision Type2: | District |
| Subdivision Name2: | Waidhofen an der Thaya |
| Parts Style: | para |
| Leader Title: | Mayor |
| Leader Name: | Siegfried Walch |
| Elevation M: | 442 |
| Population Density Km2: | auto |
| Timezone: | CET |
| Timezone Dst: | CEST |
| Utc Offset: | +1 |
| Utc Offset Dst: | +2 |
| Registration Plate: | WT |
| Postal Code Type: | Postal code |
| Postal Code: | 3822 |
| Area Code Type: | Area code |
| Area Code: | 02844 |
| Website: | www.karlstein-thaya.gv.at |
Karlstein an der Thaya is a municipality and market town in the district of Waidhofen an der Thaya in the Austrian state of Lower Austria.
Elections were held in 2015 with the following results: