Throughout the world, Koornstra (Koornstra 
) is an extremely rare unknown gender first name. Predominantly, Koornstra is the last name as well as the forename.
| VARIANT | COUNTRY |
|---|---|
| Koornstra | Netherlands, Canada, United States, Argentina, North Macedonia |
|
metten koornstra Dutch painter (1912-1978), NL (b. 1912) |
|