In short

To tell someone politely to do something, attach -(으)세요 to the verb stem: -세요 after a vowel, -으세요 after a 받침. To tell them not to, use -지 마세요. For a warmer, favour-asking tone, use -아/어 주세요 (please do it for me). Only action verbs take commands - to ask for a state, turn the adjective into an adverb and add a verb (조용히 하세요); a few set well-wishes like 건강하세요 are the exception.

The rule

Step 1 - The polite command is -(으)세요, chosen by the 받침

Verb stem + -(으)세요

The ending has two shapes, picked by the last sound of the stem - exactly the vowel-vs-받침 split you already know from 은/는 and -(으)면:

• stem ends in a vowel -> -세요: 가다 -> 가세요 (gaseyo, please go)
• stem ends in any 받침 -> -으세요: 읽다 -> 읽으세요 (ilgeuseyo, please read), 앉다 -> 앉으세요 (anjeuseyo, please sit)

Because the 받침 form inserts a vowel -으, it triggers irregular stems just like any vowel-initial ending: 듣다 -> 들으세요 (deureuseyo, please listen), not *듣으세요.

Step 2 - ㄹ-stems drop their ㄹ

A stem ending in ㄹ loses the ㄹ before -세요 and takes the vowel form, never *-으세요:

• 살다 -> 사세요 (saseyo, please live; the same shape as 사다 buy -> 사세요, so context decides which)
• 만들다 -> 만드세요 (mandeuseyo, please make it)
• 팔다 -> 파세요 (paseyo, please sell)

This is the same ㄹ-deletion you met in lesson 17: ㄹ falls out in front of ㅅ, ㄴ and ㅂ.

Step 3 - Where -(으)세요 comes from, and why it is polite

-(으)세요 is the subject-honorific -(으)시- (lesson 22) fused with 해요체 -어요: -(으)시- + -어요 -> -(으)세요. So the ending does two jobs at once - it is polite to the listener and it raises the subject you are addressing. This is exactly why you never point it at yourself: *저는 앉으세요 is wrong. Command forms are always about the other person.

Step 4 - Softer and more deferential requests

A bare -(으)세요 is a clear instruction. Two patterns soften it:

• -아/어 주세요 - do it for me, as a favour. Build the 아/어 form (lesson 10) and add 주세요 (juseyo, from 주다 give), with a space: 기다려 주세요 (gidaryeo juseyo, please wait for me), 읽어 주세요 (ilgeo juseyo, please read it to me). A few of these have fused into single dictionary words and so lose the space - 도와주세요 (dowajuseyo, please help me), from the headword 도와주다. Treat it as a fixed pattern for now; the full benefactive machine is lesson 33.
• -(으)시겠어요? - the most deferential, a would you…? offer: 앉으시겠어요? (anjeusigesseoyo?, would you like to sit?).

And the plain 해요체 form (lesson 12) is gentler still than -(으)세요 - 여기 앉아요 (yeogi anjayo, sit here) - but it does not raise the subject, so use it only with people at or below your level.

Step 5 - Prohibition: -지 마세요

To forbid an action, attach -지 마세요 to the stem. You cannot negate a command with 안 - *안 가세요 does not mean don’t go.

Verb stem + -지 마세요

• 가다 -> 가지 마세요 (gaji maseyo, please don’t go)
• 만지다 -> 만지지 마세요 (manjiji maseyo, please don’t touch)

The 마세요 part is the honorific command of 말다 (malda, to stop / desist), a ㄹ-stem - so its ㄹ drops (Step 2): 말- + -세요 -> 마세요, never *말세요. The softer 해요체 version is -지 마요 (가지 마요, gaji mayo), and the casual and formal forms follow the ladder in Step 7.

Step 6 - A few verbs have a suppletive honorific command

When you address someone you respect, a handful of everyday verbs swap for a completely different honorific word (the full set is lesson 22):

• 먹다 / 마시다 -> 드세요 (deuseyo, please eat / drink): 많이 드세요 (mani deuseyo, do help yourself)
• 자다 -> 주무세요 (jumuseyo, please sleep): 안녕히 주무세요 (annyeonghi jumuseyo, good night)
• 있다 -> 계세요 (gyeseyo, please stay): 안녕히 계세요 (annyeonghi gyeseyo, goodbye, to the one staying)
• 말하다 -> 말씀하세요 (malsseumhaseyo, please speak, go ahead)

Never use these of yourself - *저는 드세요 / *저는 계세요 are register errors.

Step 7 - Adjectives cannot be commanded

An imperative demands an action, but a 형용사 (lesson 11) describes a state, and you cannot order a state into being: 예쁘세요 (yeppeuseyo) and 바쁘세요 (bappeuseyo) have no be pretty / be busy reading. Careful, though - those strings are not ungrammatical. -(으)세요 is a mood-neutral ending, so on an adjective - and equally on the stative verbs 알다 and 있다 - it is just as readily read as an honorific statement or question: 예쁘세요 = you are pretty (a compliment you will hear often), 바쁘세요? = are you busy?, 아세요? = do you know?, 세 분 계세요 = three people are here (a description, not an order - though 계세요 really is one in 안녕히 계세요). The everyday exception is a handful of set well-wishes - 건강하세요 (stay healthy), 행복하세요 (be happy) - which you will hear constantly, although careful usage prefers a verb: 건강하게 지내세요. To actually ask for the state, say it with a verb - turn the adjective into an adverb with -게/-히 and add a verb: 조용하세요, which careful usage reads as you are quiet, -> 조용히 하세요 (joyonghi haseyo, please be quiet = do it quietly). -게 is the productive half and attaches straight to the plain stem, with no 받침 alternation: 좋다 -> 좋게 (joke), 예쁘다 -> 예쁘게 (yeppeuge), 조용하다 -> 조용하게 (joyonghage, the same adverb as 조용히). Most adjectives have no -히 form at all, so -게 is the one that always works (lesson 37).

Forms & patterns

-(으)세요, chosen by the last sound of the stem:

The softening scale, same verb 기다리다 (wait):

Prohibition -지 마세요 across the registers:

Suppletive honorific commands (full set in L22):

The command ladder, verb 하다 (do):

Examples

Common mistakes

• 읽세요. (Ikseyo.) -> 읽으세요. (Ilgeuseyo.) - 읽다 ends in a 받침, so the command is -으세요. The bare -세요 belongs only to vowel-final stems like 가세요.
• 가지 말세요. (Gaji malseyo.) -> 가지 마세요. (Gaji maseyo.) - 마세요 comes from 말다, a ㄹ-stem, and ㄹ drops before -세요. Writing the ㄹ back in is the classic ㄹ-stem slip.
• 여기 안 앉으세요. (Yeogi an anjeuseyo.) -> 여기 앉지 마세요. (Yeogi anji maseyo.) - You cannot forbid an action with 안. Prohibition needs the -지 마세요 pattern.
• 조용하세요. (Joyonghaseyo.) -> 조용히 하세요. (Joyonghi haseyo.) - 조용하다 is an adjective, so careful usage reads -(으)세요 on it as a statement (you are quiet), not as the command you meant. Make it an adverb plus the verb 하다.
• (leaving, to the one staying) 안녕히 가세요. -> 안녕히 계세요. (Annyeonghi gyeseyo.) - Say 가세요 (go well) to the person who is leaving and 계세요 (stay well) to the one who stays; learners swap them.

Tips

• -(으)세요 = -(으)시- + 해요. It bows to the listener and lifts the subject in one ending. That double duty is exactly why it never points at you - a command form is always about the other person.
• The command ladder, top to bottom: 해 (friend) < 해요 (gentle) < 하세요 (polite default) < 하십시오 (formal). With a stranger, 하세요 is always safe; among friends drop to 해요 or 해.
• -아/어 주세요 literally means “do it and give.” The 주다 (give) frames the action as a favour to you, so it lands warmer and less bossy than a bare 하세요. Reach for it whenever you are asking, not instructing.
• Public signs speak 합쇼체. You will read -지 마십시오 everywhere - 들어가지 마십시오 (do not enter), 담배를 피우지 마십시오 (no smoking) - even though you yourself will say 마세요.