All around the world, Ísleifur (Ísleifur 
) is a very rare boy's forename. The forename Ísleifur is habitual in Northern Europe, particularly Iceland, where it is quite a rare male name.
| VARIANT | COUNTRY |
|---|---|
| Ísleifur | Iceland |
| ísleifur gissurarson Icelandic bishop, IS (b. 1006) |
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| ísleifur einarsson (b. 1765) |
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| ísleifur sesselíus konráðsson Icelandic painter, IS (b. 1889) |
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| ísleifur friðriksson icelandic sailor (b. 1956) |
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Jónsson, Tómasson, Árnason, Birgisson, Gissurarson, Ásgrímsson, Guðmundsson, and Guðmannsson