Cognomen Hapuoja (Hapuoja 
) , all around the world, is a rare surname. The cognomen Hapuoja is habitual in Northern Europe, particularly Finland, where it is quite a rare surname, Norway, where it is a rare surname, and the United Kingdom, where it is an extremely rare surname.
| VARIANT | COUNTRY |
|---|---|
| Hapuoja | Finland, Norway, United Kingdom |
| maija hapuoja Finnish singer, FI (b. 1948) |
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| jukka hapuoja Finnish choral and orchestral conductor |
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