-고 Grammar: The Korean And-Connector for Verbs
-고 is Korean's all-purpose "and" for verbs: attach it to a verb stem to link two actions in one sentence, with tense marked only on the final verb — 먹고 자요 (eat and sleep). It's also the connector hiding inside 고 있다 (doing it now) and 고 싶다 (want to). Use 아/어서 instead when the first action directly causes the second.
Textbooks teach -고 in week two as "the word for and," hand you 먹고 자요, and move on. What they skip is that -고 isn't one grammar point — it's a whole family. You've already met three or four of its children without anyone telling you they were related. Let's fix that.
The basic move: two verbs, one -고
Drop the 다 off a verb, add -고, and you've glued it to the next clause. The subject only needs to appear once, and — this is the part learners forget — tense only goes on the very last verb. Everything before -고 stays in its bare stem form, no matter what tense the sentence ends up in.
저는 밥을 먹고 자요.
jeo-neun ba-beul meok-go ja-yo.
I eat and (then) sleep.
Two actions, one sentence — just -고 between them, no separate word for "and."
숙제하고 놀았어요.
suk-je-ha-go no-ra-sseo-yo.
I did homework and (then) played.
Past tense (-았/었) lives only on 놀다, the final verb — 숙제하고, never 숙제했고.
이 가방은 가볍고 예뻐요.
i ga-bang-eun ga-byeop-go ye-ppeo-yo.
This bag is light and pretty.
-고 links descriptive verbs (adjectives) too — no sequence, just a list of qualities.
Notice the third row does something slightly different — 가볍다 and 예쁘다 aren't happening one after another, they're both just true at once. -고 doesn't care. It connects clauses; whether that reads as "then" or "and also" is just context.
-고's family tree: 있다, 싶다, and 나서
Here's the part nobody points out: 고 있다 and 고 싶다 aren't separate grammar rules you memorized by accident. They're -고 doing its normal job — connecting a verb to whatever comes next — except what comes next happens to be 있다 ("exist, be") or 싶다 ("want"). Once you see the pattern, three "different" grammar points collapse into one.
| Pattern | What it adds | Example |
|---|---|---|
| -고 (plain) | and / and then | 먹고 자요 — eat and sleep |
| -고 있다 | in the middle of doing it | 먹고 있어요 — I'm eating (right now) |
| -고 싶다 | want to do it | 쉬고 싶어요 — I want to rest |
| -고 나서 | after finishing doing it | 먹고 나서 나갈게요 — after I eat, I'll head out |
-고 나서 is the sequence upgrade. Plain -고 can be loose about timing — sometimes it's a strict sequence, sometimes just a list. -고 나서 removes the ambiguity: the first action has to be fully done before the second starts. If you want to stress "only after that, then this," reach for 나서.
-고 vs 아/어서: two different kinds of "and"
This is the mix-up that actually matters. Both -고 and 아/어서 translate as "and" in a dictionary, and that's exactly why learners swap them by accident. The real difference: -고 just lists events in order. 아/어서 says the first event is the reason the second one happened — the clauses are causally glued, not just adjacent.
| -고 | 아/어서 | |
|---|---|---|
| Meaning | and / and then (order or list) | and so (cause → result) |
| Relationship | loose — could be unrelated events | tight — first event explains the second |
| Example | 친구를 만나고 커피를 마셨어요 (met a friend, then separately drank coffee) | 친구를 만나서 반가웠어요 (meeting my friend IS why I felt glad) |
Quick test: can you insert "because of that" between the two clauses without it sounding forced? If yes, 아/어서. If the two events are just... both true, in order, -고. That's why 만나서 반가워요 ("nice to meet you" — literally "meeting-and-so, [I'm] glad") never becomes 만나고 반가워요. The gladness isn't caused by the meeting in that version; it just sits next to it, which sounds like something's missing.
Compliment-stacking: -고's favorite party trick
Once you have -고, you can chain as many clauses as you want, not just two — which is exactly how Koreans build a run-on compliment (or a run-on complaint). String three adjectives together with -고 and you get a rhythm that sounds natural, not like a checklist.
야, 어제 소개팅 어땠어?
ya, eo-je so-gae-ting eo-ttae-sseo?
Hey, how was the blind date yesterday?
완전 좋았어. 예쁘고 착하고 되게 똑똑하더라.
wan-jeon jo-a-sseo. ye-ppeu-go cha-ka-go doe-ge ttok-tto-ka-deo-ra.
It was great. She's pretty, and sweet, and turns out really smart.
헐, 번호 땄어?
heol, beon-ho tta-sseo?
Whoa, did you get her number?
당연하지.
dang-yeon-ha-ji.
Obviously.
Where -고 gets used without you noticing
Once you start listening for -고, you'll hear it everywhere: 씻고 나갈게요 (I'll wash up and head out), 앉고 얘기하자 sounding wrong the second you say it out loud because sitting doesn't cause talking — see, the 아/어서 instinct kicks in automatically once you've drilled the contrast a few times. -고 is quietly one of the most-used endings in the language precisely because it's the default, judgment-free "and." It doesn't ask why two things happened together. It just says they did.
Frequently asked questions
What does -고 mean in Korean grammar?
-고 is a connective ending attached to a verb or adjective stem, meaning "and" or "and then." It links two clauses into one sentence, stating the subject once and putting tense only on the final verb — 먹고 자요 (eat and sleep), 밥을 먹고 잤어요 (ate and then slept).
Is -고 the same grammar as 고 있다 and 고 싶다?
Same root, different job. 고 있다 (doing it right now) and 고 싶다 (want to do it) are fixed compounds where -고 connects a verb stem to 있다 ("be/exist") or 싶다 ("want"). Plain -고 without a following helper verb just means "and" between two independent clauses.
When do I use -고 instead of 아/어서?
Use -고 for simple sequence or listing with no cause-effect link: 밥 먹고 학교 가요 (eat, then go to school). Use 아/어서 when the first action directly causes or explains the second: 늦어서 미안해요 (sorry BECAUSE I'm late). If "because of that" doesn't fit between the clauses, -고 is the safer choice.
Can -고 connect adjectives, not just verbs?
Yes — Korean adjectives conjugate like verbs (grammarians call them descriptive verbs), so -고 links them the same way: 예쁘고 착해요 (pretty and kind). This is exactly the pattern behind compliment-stacking sentences like 예쁘고 착하고 똑똑해요.
What's the difference between -고 and -고 나서?
-고 나서 means "after finishing doing X" — it locks in that the first action is completely done before the second starts: 숙제하고 나서 놀아요 (after finishing homework, I play). Plain -고 can leave that timing looser, especially when listing unrelated or simultaneous actions.
Does the subject have to be the same in both clauses?
Usually yes for the smoothest reading — 저는 밥을 먹고 자요 keeps "I" as the subject of both eating and sleeping. Different subjects are grammatically possible (친구는 요리하고 저는 설거지해요 — my friend cooks and I wash up), but the sentence reads more like two separate facts than one flowing action.