도: Also, Too — and the Particle It Replaces

도 means also, too, as well. Simple enough. The part that trips people is what happens to the particle that was already there.

It replaces, it does not stack

This is the rule.

저는 학생이에요.   →  저도 학생이에요.     ✅  I'm a student too.
                  →  저는도 학생이에요.   ❌

도 takes over the slot that 은/는 vs 이/가 was occupying. Both cannot be there at once, so 는 drops out entirely.

The same happens with the other role-marking particles:

이/가 and 을/를 disappear the same way. None of them survive alongside 도.

Except when they do

Now the exception, and it has a clean logic.

학교에 갔어요.   →  학교에도 갔어요.    ✅  I went to school too.

에 stays. So do 에서, 한테, 로 and the rest.

The difference: 은/는, 이/가, 을/를 only mark a grammatical role. They carry no meaning of their own, so 도 can absorb their job.

에, 에서, 한테, 로 carry actual meaning — direction, location, recipient. 도 cannot express any of that, so it attaches after them rather than replacing them.

• 친구한테도 말했어요 — I told my friend too.
• 집에서도 일해요 — I work at home as well.
• 부산에도 가 봤어요 — I’ve been to Busan too.

Once you see that split, you never have to memorise a list.

In negative sentences

Same particle, and English switches words where Korean does not.

A: 저는 안 가요. — I’m not going.
B: 저도 안 가요. — I’m not going either.

English needs either; Korean just keeps 도. This extends to a family of fixed negatives:

• 아무것도 안 먹었어요 — I didn’t eat anything at all.
• 한 번도 안 가 봤어요 — I’ve never been, not once.
• 아무도 안 왔어요 — Nobody came.

All of these require a negative verb. 아무것도 먹었어요 is broken — the 도 is waiting for the 안.

The opposite: 만

만 means only, and it lives in the same slot:

저도 갔어요 — I went too.
저만 갔어요 — Only I went.

Same replacement behaviour, opposite meaning. If you have learned one, you have learned the shape of the other.

The one to actually use today

저도 — me too.

A: 저는 한국 드라마를 좋아해요.
B: 저도요!

저도요 with the polite 요 attached is a complete reply on its own. It is probably the most useful two-syllable response a beginner can carry around.