The Apostrophe-S Error

This is one of the most predictable errors an English speaker makes in Norwegian, and one of the easiest to fix once you see it. To show possession, Norwegian adds -s directly to the owner's name — Olas bil, Norges flagg, barnets rom — with no apostrophe. English writes the identical construction with an apostrophe (Ola's car), and because the two look almost the same, your hand inserts the apostrophe automatically. The fix is a one-line proofreading rule, so this page exists mainly to make you see the apostrophe you are about to type and delete it.

The rule: -s attaches directly, no apostrophe

The Norwegian genitive is formed by gluing -s straight onto the noun or name. No space, no apostrophe, no extra letters. It looks exactly like the English possessive minus the apostrophe.

The genitive -s works on ordinary nouns and on the definite form too: barnet (the child) → barnets (the child's), jenta (the girl) → jentas (the girl's), læreren (the teacher) → lærerens (the teacher's). In every case the -s simply joins on the end. There is no apostrophe anywhere in standard Norwegian possession — not on names, not on common nouns, not on definite nouns.

The one exception: names ending in s, x or z

There is exactly one place an apostrophe is correct, and it is a substitute for the -s, not an addition to it. When a name already ends in -s, -x or -z, you do not add a second -s (which would be hard to say and look odd). Instead you add a bare apostrophe after the existing final letter.

So the logic is the reverse of the English speaker's instinct. In English you reach for the apostrophe first and the -s second (Ola's). In Norwegian there is normally no apostrophe at all, and the apostrophe only shows up in place of an -s that would otherwise be awkward after an existing s/x/z. The apostrophe is a sign that you have withheld the -s, not that you are adding one.

Never an apostrophe in plurals

A second strand of the same transfer error is the "greengrocer's apostrophe" — sticking an apostrophe into a plural. English speakers sometimes do this even in English; in Norwegian it is simply never correct. Plural -er/-e/-r endings take no apostrophe, and neither does the genitive of a plural.

Note guttenes — even when the owner is plural and the meaning is "the boys'", Norwegian just stacks the -s onto the plural definite form. No apostrophe sneaks in for plurality.

The spoken escape hatch: huset til Ola

In everyday speech, Norwegians often sidestep the genitive -s altogether and use a til (to/of) construction instead — particularly with people and especially in casual registers and many dialects. This is not lazy; for a great deal of spoken Norwegian it is the more natural option, while the -s genitive leans more formal and written.

Two things to notice. First, the til construction keeps the noun in its definite form (huset, bilen, boka — "the house of Ola"), whereas the -s genitive does not (Olas hus, not Olas huset). Second, til neatly removes the apostrophe decision: there is no -s to attach, so there is no apostrophe to get wrong. If you are ever unsure how to spell Anders' or Marx', you can always say boka til Anders / teoriene til Marx and be completely safe.

Common Mistakes

The headline error. Per's is English; Norwegian is Pers — same letters, no apostrophe.

Even with everyday family words, the -s attaches bare: mammas, pappas, Karis.

This is the opposite slip: when the name ends in -s, you do need the apostrophe (replacing the absent second -s). Anders bok without it reads as no genitive at all.

Never put an apostrophe in a plural. The greengrocer's apostrophe is wrong in Norwegian, full stop.

The -s genitive forces the indefinite noun (Olas hus), unlike the til construction which keeps the definite (huset til Ola). Don't mix the two.

Key Takeaways

• The Norwegian genitive is a bare -s glued straight onto the owner — no apostrophe: Olas bil, Norges flagg, barnets rom.
• An apostrophe appears only when the name already ends in s, x or z, and then it replaces the -s: Anders', Marx', Lars' — never Anders's.
• Never put an apostrophe in a plural (to biler, not to bil's).
• The genitive -s keeps the noun indefinite (Olas hus); the spoken til alternative keeps it definite (huset til Ola) and sidesteps the apostrophe entirely.
• One-line proofreading rule: delete the apostrophe unless the name ends in s/x/z.