Family name תאודור (Theodore 
, Theodor 
, Teodor , among others...) , in the entire world, is a common surname. The cognomen תאודור is characteristic of Saint Lucia, where it is a common surname, Dominica, where it is quite a common surname, and Poland (explore the name in all countries). Measured by absolute frequency, it is commonest in Poland, Romania, and the United States. More frequently, תאודור is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Theodore | Romania, Germany, South Africa, Cameroon, United States |
| Theodor | Romania, Germany, Poland, United States, Cameroon |
| Teodor | Romania, Germany, South Africa, Poland, United States |
| Théodore | Germany, Cameroon, United States, Ethiopia, Ivory Coast |
| Теодор | Ukraine, Kazakhstan, Bulgaria, Russia, Serbia |
| תאודור | Israel |
קוסטה, קליין, רוטשטיין, and דונאייבסקי