English has one flat, invariable word for "both" — it never changes for gender, and it never changes for case. Ukrainian has three words for "both," and they decline. This is one of those places where English gives you no warning at all: you have to choose оби́два, оби́дві, or обо́є by gender and by whether you are counting people or paired things, and then bend the whole phrase through the cases. This page sorts out the choice, the declension, and the neighbouring vocabulary of pairs and sets (па́ра, дво́є двере́й) that Ukrainian uses where English just says "two."
The three forms of "both"
The split mirrors the split in the word for "two" (два / дві), plus a third collective form for people:
| Form | Used for | Noun goes in | Example |
|---|---|---|---|
| оби́два | masculine & neuter | nominative plural | оби́два бра́ти, оби́два вікна́ |
| оби́дві | feminine | nominative plural | оби́дві сестри́, оби́дві руки́ |
| обо́є | people / mixed-gender group | genitive plural | обо́є діте́й, обо́є батькі́в |
The key contrast hides in that third column. Оби́два and оби́дві work exactly like два and дві: they take the noun in the nominative plural (оби́два бра́ти, not обо́х брати́в). But *обо́є is a true collective, like дво́є and тро́є, so it takes the genitive plural (обо́є діте́й). Get the case of the noun wrong and the whole phrase sounds off.
Оби́два бра́ти ви́вчилися на лі́карів — батьки́ ду́же ни́ми пиша́ються.
Both brothers trained as doctors — their parents are very proud of them.
Оби́дві сестри́ закі́нчили той са́мий університе́т, що й ма́ма.
Both sisters graduated from the same university as their mum.
Обо́є діте́й захворі́ли одно́часно — оце́ був ти́ждень.
Both children got sick at the same time — what a week that was.
When to reach for обо́є
Use обо́є when the two are people taken as a pair, especially a couple or a mixed-gender pair, or when you are not foregrounding their gender at all. It is the natural word for "both of them" about a married couple, two friends, parents, partners.
Вони́ одружи́лися мину́лого ро́ку, і обо́є зра́зу зна́йшли робо́ту в Льво́ві.
They got married last year, and both of them found work in Lviv straight away.
Я запита́в обо́х, але́ ні́хто з них не зна́в, де ключі́.
I asked both of them, but neither knew where the keys were.
Обо́є друзі́в прийшли́ зі свої́ми дівчи́нами — ве́чір був галасли́вий.
Both friends came with their girlfriends — it was a noisy evening.
They all decline — and share one oblique set
Here is the part English speakers never expect: as soon as the phrase leaves the nominative, "both" changes shape. And the good news is that all three forms collapse into one set of oblique forms. You do not have to learn three declensions — you learn оби́два/оби́дві/обо́є in the nominative, and a single oblique paradigm for everything else.
| Case | Form | With a noun |
|---|---|---|
| Nominative | оби́два / оби́дві / обо́є | оби́два бра́ти |
| Genitive | обо́х | обо́х брати́в |
| Dative | обо́м | обо́м брата́м |
| Accusative | = nom. (things) / = gen. (people) | оби́два столи́ / обо́х брати́в |
| Instrumental | обо́ма | обо́ма брата́ми |
| Locative | (на) обо́х | на обо́х бе́регах |
In the oblique cases the numeral and the noun move together: both go into the same case (обо́х брати́в, обо́м брата́м, обо́ма брата́ми). The distinctive masculine/feminine/collective shapes survive only in the nominative (and the inanimate accusative). The moment a preposition or a verb pulls the phrase into the genitive, dative, instrumental or locative, you say обо́х, обо́м, обо́ма regardless of gender.
Я поговори́в з обо́ма ліка́рями, і їхні ду́мки збіга́ються.
I spoke with both doctors, and their opinions agree.
В обо́х кварти́рах одна́кове планува́ння, ті́льки по́верх рі́зний.
Both flats have the same layout, only the floor is different.
Обо́м ді́вчинкам купи́ли одна́кові ра́нці — тепе́р їх не розрі́зниш.
They bought both girls identical backpacks — now you can't tell them apart.
Adjectives inside the phrase
If an adjective sits between "both" and the noun, its case follows the same logic as with два/дві. After оби́два/оби́дві the noun is nominative plural, and a masculine/neuter adjective there typically takes the genitive plural (оби́два висо́ких юнаки́), while a feminine adjective stays nominative plural (оби́дві висо́кі дівчи́нки) — exactly as it does after два and дві. This is the standard numeral-agreement pattern, covered in full on the numeral-agreement page.
Оби́два ста́рших си́ни вже живу́ть окре́мо, з на́ми лиши́вся ме́нший.
Both elder sons already live separately; the younger one stayed with us.
"Both" with plural-only nouns: use обо́є
Some nouns exist only in the plural — две́рі "door," окуля́ри "glasses," но́жиці "scissors," штани́ "trousers." With these, оби́два/оби́дві can't latch on (just as cardinal два can't), and you reach for the collective обо́є + genitive plural, the same way you would use дво́є. See the plurale-tantum page for the wider list.
Обо́є двере́й у ста́рій ха́ті рипі́ли так, що буди́ли всіх.
Both doors in the old house creaked so much they woke everyone up.
Counting a pair: па́ра + genitive
When you mean a pair as a unit — a matching set of two — Ukrainian uses the noun па́ра "a pair," and what it pairs goes into the genitive (plural for countable things). This is how you say "a pair of shoes / gloves / socks," and it is also the idiomatic way to count plural-only clothing.
Купи́, будь ла́ска, па́ру шкарпе́ток — мої́ всі в ди́рках.
Please buy a pair of socks — all of mine have holes.
На розпро́дажі я взяла́ дві па́ри чобі́т за ціно́ю одніє́ї.
In the sale I got two pairs of boots for the price of one.
Note that па́ра also drifts into the colloquial meaning "a couple, a few" (па́ра хвили́н "a couple of minutes"), where it shades toward the approximate — but its core, countable sense is the matched set of two.
Collective дво́є/тро́є for sets and pairs
For paired objects and plural-only nouns more generally, Ukrainian leans on the collective numerals дво́є, тро́є, че́тверо + genitive plural. This is not "both" but plain "two / three," and it is required wherever the cardinal два/три cannot count (the plural-only nouns) and idiomatic for groups of people and paired things. The full system — including the genitive-plural government and the oblique forms двох/трьох — lives on the collective-numerals page; here is the connection to pairs.
У комо́рі лежа́ть дво́є стари́х окуля́рів і тро́є рукави́ць без па́ри.
In the pantry there are two old pairs of glasses and three gloves without a match.
Нам потрі́бно дво́є двере́й для но́вої комі́рки.
We need two doors for the new storage room.
So the division of labour is clean: обо́є = "both" of a plural-only or people set; дво́є/тро́є = plain "two/three" of the same; па́ра = a matched unit of two.
Source-language comparison
For an English speaker, three things are genuinely new here. First, "both" is gendered: оби́два for masculine/neuter, оби́дві for feminine, обо́є for people — English never marks this. Second, "both" declines: "with both brothers" is з обо́ма брата́ми, "to both girls" is обо́м ді́вчинкам — English keeps "both" frozen in every position. Third, the case of the noun depends on which form you chose: nominative plural after оби́два/оби́дві, but genitive plural after обо́є — a distinction with no English shadow at all. The mental discipline is to pick the form by gender/people first, then set the noun's case to match.
For a learner coming through Russian, the forms are close but not identical, and the danger is importing Russian shapes. Ukrainian's oblique is обо́х / обо́м / обо́ма — do not stretch them into обо́їх / обо́їм, and do not say оби́двома for the instrumental. And keep the apostrophe-free spelling обо́є (it ends in -оє, like дво́є, тро́є).
Common Mistakes
❌ оби́два сестри́ (masculine 'both' with a feminine noun)
Incorrect — feminine 'both' is оби́дві: оби́дві сестри́.
✅ оби́дві сестри́
both sisters — feminine оби́дві + nominative plural.
❌ з обо́їма брата́ми / з оби́двома брата́ми
Incorrect — the instrumental of 'both' is обо́ма: з обо́ма брата́ми.
✅ з обо́ма брата́ми
with both brothers — обо́ма is the only instrumental form.
❌ обо́є бра́ти (nominative plural after обо́є)
Incorrect — the collective обо́є governs the genitive plural: обо́є брати́в.
✅ обо́є брати́в
both brothers — обо́є + genitive plural (or simply оби́два бра́ти).
❌ оби́два брати́в (genitive plural after оби́два)
Incorrect — оби́два works like два and takes the nominative plural: оби́два бра́ти.
✅ оби́два бра́ти
both brothers — оби́два + nominative plural.
❌ па́ра чо́боти (nominative for what is paired)
Incorrect — па́ра governs the genitive: па́ра чобі́т.
✅ па́ра чобі́т
a pair of boots — па́ра + genitive plural.
Key Takeaways
- "Both" is gendered: оби́два (masc./neut.), оби́дві (fem.), обо́є (people/mixed) — choose by gender and by whether you mean people.
- The case of the noun follows the form: nominative plural after оби́два/оби́дві (оби́два бра́ти), but genitive plural after обо́є (обо́є діте́й).
- All three share one oblique set: обо́х (gen./loc.), обо́м (dat.), обо́ма (instr.) — never обо́їх, обо́їм, *оби́двома.
- Use обо́є with plural-only nouns (обо́є двере́й), where оби́два/оби́дві cannot attach.
- Pairs and sets: па́ра
- genitive (па́ра чобі́т) for a matched unit; the collective дво́є/тро́є
- genitive plural for plain "two/three" of people and paired things.
- genitive (па́ра чобі́т) for a matched unit; the collective дво́є/тро́є
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Start learning Ukrainian→Related Topics
- Collective Numerals (Двоє, Троє, Четверо)B1 — Ukrainian's second set of low numbers — дво́є, тро́є, че́тверо, п’я́теро… — used for groups of people (нас було́ че́тверо), plural-only nouns where two/three fail (тро́є двере́й), and the young of animals (че́тверо кошеня́т); they govern the genitive plural and signal a warm, cohesive group, with два́ vs дво́є being a register choice English has no parallel for.
- Numeral–Noun Agreement (The Hard Part)B1 — The notorious three-way rule: after 1 (and …1) the noun is nominative SINGULAR, after 2/3/4 (and …2/3/4) nominative PLURAL with the dual-reflex end-stress (два столи́, дві сестри́), and after 5+ genitive PLURAL — chosen by the LAST digit, and applying only when the whole phrase is nominative or inanimate-accusative.
- Plural-Only and Singular-Only NounsB1 — Some Ukrainian nouns are locked to one number: plurale tantum like двері, гроші, окуляри exist only in the plural and take plural agreement, while singularia tantum like молоко, щастя and the collective -я neuters like волосся, листя exist only in the singular — and the grammar often runs opposite to English.
- Grammatical Gender: Masculine, Feminine, NeuterA1 — Ukrainian sorts every noun into three genders — masculine, feminine, neuter — and you can predict which about 90% of the time from the nominative singular ending; gender then drives all adjective, pronoun, and past-tense agreement, so it must be learned with each word.
- Genitive Plural: FormsB1 — Ukrainian's hardest ending set, taught as a procedure: the zero ending for feminine -а/-я and neuter -о (often with a fleeting vowel — кни́га→книг, вікно́→ві́кон, сестра́→сесте́р), the -ів/-їв ending for masculines (стіл→столі́в, брат→браті́в), and -ей for soft-feminine -ь and many soft/hushing stems (ніч→ноче́й, кінь→коне́й), with the о/і alternation surfacing in zero-ending forms (нога́→ніг, гора́→гір, шко́ла→шкіл).
- Numeral Agreement MistakesB1 — The errors that give away a non-native — or a Russian-trained — speaker after numbers. The headline trap is два стола (Russian genitive singular) instead of the Ukrainian два столи́ (NOMINATIVE PLURAL) for 2/3/4; then forgetting that 5+ forces the genitive plural (п’ять столі́в), that compounds follow their LAST digit (два́дцять оди́н стіл, два́дцять п’ять столі́в), that 'years' is suppletive (оди́н рік, два ро́ки, п’ять ро́ків), and that an oblique numeral must decline (з двома́ друзя́ми).