"Both": oba, obie, obaj, oboje | Polish Grammar

English has one word, "both," for every kind of pair. Polish has four, because "both" inherits the entire gender machinery of the number "two." Just as you must choose between dwa, dwie, dwaj/dwóch and dwoje depending on what you're counting, you must choose between oba, obie, obaj/obu and oboje for "both." "Both books" is obie książki (feminine), "both windows" is oba okna (neuter), "both brothers" is obaj bracia (men), and "both parents — mother and father" is oboje rodzice (mixed sex). Choosing wrong is exactly the same trap as with dwa: it marks you as a learner instantly. This page lines all four up against their dwa-counterparts so the choice becomes mechanical.

The four-way split

Counts…	"two"	"both"	Example
Masculine inanimate / animal + neuter	dwa	oba	oba koty, oba okna — both cats, both windows
Feminine	dwie	obie	obie książki, obie siostry — both books, both sisters
Masculine-personal (men)	dwaj / dwóch	obaj / obu	obaj bracia / obu braci — both brothers
Mixed-sex / collective	dwoje	oboje	oboje rodzice — both parents (mother + father)

The mapping is one-to-one with "two." If you know which form of dwa a noun takes, you automatically know which form of "both" it takes. This is the single most efficient way to learn it: don't memorize "both" separately — derive it from "two."

💡

One rule does all the work: "both" copies the gender form of "two." dwa → oba, dwie → obie, dwaj/dwóch → obaj/obu, dwoje → oboje. Learn the parallel, not four separate words.

oba — masculine inanimate, animals, and neuter

Use oba for masculine non-personal nouns (objects, animals) and for neuter nouns. It pairs with the noun in the nominative plural, just like dwa.

Oba samochody stoją w garażu.

Both cars are in the garage. (masc. inanimate → oba)

Oba okna trzeba pomalować.

Both windows need painting. (neuter → oba)

Posprzątałem oba pokoje przed wizytą.

I cleaned both rooms before the visit. (masc. inanimate, accusative → oba)

obie — feminine

Use obie for feminine nouns. It is the direct counterpart of dwie.

Obie siostry studiują w Krakowie.

Both sisters study in Kraków. (feminine → obie)

Przeczytałam obie książki w jeden weekend.

I read both books in one weekend. (feminine, accusative → obie)

obaj / obu — masculine-personal (men)

For groups of men you have, exactly as with "two," two constructions: obaj (+ nominative plural) and obu (+ genitive plural), the latter being very common in speech. Obu also serves as the general oblique stem.

Obaj bracia pracują w tej samej firmie.

Both brothers work at the same company. (men → obaj + nominative plural)

Znam obu kandydatów osobiście.

I know both candidates personally. (men, accusative → obu + genitive plural)

oboje — mixed-sex and collective

When the pair contains a man and a woman — a couple, both parents, a brother and sister — you must use oboje, the collective "both," parallel to dwoje. It governs the genitive and takes a neuter singular verb, exactly like the collective numerals (see Collective numerals).

Oboje rodzice pracują na pełen etat.

Both parents work full-time. (mother + father → oboje)

Oboje wyglądali na zmęczonych po podróży.

They both looked tired after the journey. (a mixed pair → oboje)

Zaprosiliśmy oboje — i Marka, i Kasię.

We invited both of them — both Marek and Kasia. (mixed pair, accusative → oboje)

There is a subtlety worth flagging, because even native speakers vary. When oboje + a noun is the subject (oboje rodzice), you will hear both a plural verb (oboje rodzice pracują) and, more conservatively, a neuter singular (oboje rodziców pracowało) — the latter treats oboje strictly as a quantity word governing the genitive. The plural with the bare nominative noun (oboje rodzice) is the everyday norm. But when oboje stands alone as a pronoun ("both of them"), it normally takes a masculine-personal plural verb, because a mixed group counts as masculine-personal: Oboje przyszli "both of them came," not przyszło.

Oboje przyszli na kolację i zostali do późna.

Both of them came to dinner and stayed late. (oboje as a standalone pronoun → masc.-personal plural przyszli)

Declension

All four "both" words inflect. Conveniently, the oblique forms largely converge: the masculine-personal and the general oblique both run through obu, and the collective oboje runs through obojga. Here is the working set.

Case	oba / obie (non-personal)	obaj (men)	oboje (mixed)
Nominative	oba / obie	obaj	oboje
Genitive	obu	obu	obojga
Dative	obu	obu	obojgu
Accusative	oba / obie	obu	oboje
Instrumental	oboma / obiema	oboma	obojgiem
Locative	obu	obu	obojgu

As with all numerals in oblique cases (see Declining numerals in oblique cases), the noun moves into the same case alongside "both."

Rozmawiałem z oboma kolegami o projekcie.

I talked with both colleagues about the project. (instrumental: oboma + kolegami)

W obu przypadkach decyzja była słuszna.

In both cases the decision was right. (locative: obu + przypadkach)

To była wspólna decyzja obojga rodziców.

It was a joint decision of both parents. (genitive of mixed pair: obojga rodziców)

💡

The feminine instrumental has its own form obiema (matching dwiema): z obiema rękami "with both hands." For masculine/neuter and the mixed-personal use oboma. Both are correct in their domains; don't say obiema rękoma by mixing them.

Common Mistakes

❌ Oba siostry mieszkają za granicą.

Incorrect — sisters are feminine, so 'both' is obie, not oba.

✅ Obie siostry mieszkają za granicą.

Both sisters live abroad.

❌ Obie bracia przyjechali na święta.

Incorrect — brothers are masculine-personal, so 'both' is obaj/obu, not obie.

✅ Obaj bracia przyjechali na święta.

Both brothers came for the holidays.

❌ Obaj rodzice byli na zebraniu.

Incorrect — parents are a mixed-sex pair, so 'both' is oboje, not obaj.

✅ Oboje rodzice byli na zebraniu.

Both parents were at the meeting.

❌ Lubię oba książki.

Incorrect — books are feminine: obie książki.

✅ Lubię obie książki.

I like both books.

❌ Pomogłem oba studentom.

Incorrect — in the dative both 'both' and the noun inflect: obu studentom.

✅ Pomogłem obu studentom.

I helped both students.

Key Takeaways

"Both" mirrors "two": dwa → oba, dwie → obie, dwaj/dwóch → obaj/obu, dwoje → oboje.
oba = masculine inanimate/animal + neuter; obie = feminine; obaj/obu = men; oboje = mixed-sex.
oboje (like the collectives) governs the genitive and takes a neuter singular verb.
Oblique forms converge on obu (non-mixed) and obojga / obojgu / obojgiem (mixed); feminine instrumental is obiema.
The fastest path: never learn "both" on its own — derive it from the matching form of "two."

Now practice Polish

Reading grammar gets you part of the way. The exercises are where it sticks — free, no signup needed.

Start learning Polish→