Last name Kastmo (Kastmo 
) , around the globe, is a very rare cognomen. The family name Kastmo is habitual in Norway, where it is a rare surname, and the United States, where it is an extremely rare surname. Much less frequently, Kastmo is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Kastmo | Norway, United States, Philippines |