〜てもいい: Asking and Giving Permission in Japanese
The green light it gives
The stance behind 〜てもいい is simple: the speaker is waving an action through. Whoever says it is signalling that the action is permitted — "it's okay to do it," "you may go ahead." The literal machinery is the て-form (the connective "and/doing…") plus もいい ("is also fine"), so 食べてもいい really reads "even if you eat, it's fine." Keep the です for polite speech; drop it when you're casual.
ここに座ってもいいです。
ここに すわっても いいです。
You may sit here.
この本を読んでもいいですよ。
この ほんを よんでも いいですよ。
You can go ahead and read this book.
よ adds a friendly, reassuring tone.
モチはもう帰ってもいい。
モチは もう かえっても いい。
Mochi may go home now.
Casual — no です.
What it's built on
Everything hangs off the verb's て-form; only もいい shifts between polite and casual, while the verb itself never changes.
| Verb (dictionary) | て-form | + もいい | Meaning |
|---|---|---|---|
| 食べる (to eat) | 食べて | 食べてもいい(です) | may eat |
| 飲む (to drink) | 飲んで | 飲んでもいい(です) | may drink |
| 行く (to go) | 行って | 行ってもいい(です) | may go |
| する (to do) | して | してもいい(です) | may do |
| 来る (to come) | 来て | 来てもいい(です) | may come |
If you are shaky on building て-forms, review the て-form guide first — every pattern here depends on it.
Asking for the green light: 〜てもいいですか
Flip the stance from granting to requesting by adding か. This is the everyday way to say "May I…?" or "Is it okay if I…?"
先生、写真を撮ってもいいですか。
せんせい、しゃしんを とっても いいですか。
Teacher, may I take a photo?
ここでご飯を食べてもいいですか。
ここで ごはんを たべても いいですか。
Is it okay if I eat here?
The reply carries its own culture. A yes is the warm, common はい、どうぞ ("yes, go ahead"). A no is rarely blunt — instead a soft すみません、ちょっと… ("sorry, that's a little…") trails off, and the listener reads the unfinished sentence as the refusal.
「写真を撮ってもいいですか。」「はい、どうぞ。」
「しゃしんを とっても いいですか。」「はい、どうぞ。」
'May I take a photo?' 'Yes, go ahead.'
「ここに座ってもいいですか。」「すみません、ちょっと…。」
「ここに すわっても いいですか。」「すみません、ちょっと…。」
'May I sit here?' 'Sorry, that's a bit…' (= please don't).
The trailing ちょっと… is a gentle refusal.
From casual to formal: the politeness ladder
How permitting sounds depends on the ending you pick. Among friends, just drop です:
ヤッタン、私のペンを使ってもいい？
ヤッタン、わたしの ペンを つかっても いい？
Yattan, can I use your pen?
Casual question — rising ？ instead of か.
Climb toward the formal end by swapping いい for かまいません ("I don't mind / it doesn't matter"). The permission is identical; the tone is more polite or businesslike.
こちらの席に座ってもかまいません。
こちらの せきに すわっても かまいません。
You're welcome to sit in this seat.
てもかまいません = a slightly more formal 'it's fine to…'
Where it sits vs "don't have to" and "must not"
Two neighbours live on the "no" side of permission. You don't need them in depth yet, but recognising them keeps the stance clear:
- 〜なくてもいい = you don't have to do it (the action is optional): 来なくてもいい ("you don't have to come").
- 〜てはいけない = you must not do it (the action is forbidden): ここで写真を撮ってはいけない ("you must not take photos here").
To politely tell someone not to do something, you can also use 〜ないでください, and to politely ask them to do something, use 〜てください.
Watch-outs
- Wrong て-form. もいい can only attach to a correct て-form — 飲んでもいい (✓), not 飲みてもいい. Master the て-form first.
- Forgetting も. It's 食べてもいい, not 食べていい. The も ("even/also") is part of the pattern.
- Translating a refusal too literally. A "no" answer is usually すみません、ちょっと…, not a flat いいえ. The soft trail-off is the refusal.
- Mixing up "don't have to" and "must not." なくてもいい = optional; てはいけない = forbidden. They are not the same.
The short version
- 〜てもいい(です) = "it's okay to / you may" — built from the て-form + もいい.
- Add か to ask permission: 写真を撮ってもいいですか ("May I take a photo?").
- Reply はい、どうぞ for yes; すみません、ちょっと… for a soft no.
- Casual: drop です. Slightly formal: 〜てもかまいません.
- Opposites: なくてもいい (don't have to) and てはいけない (must not).
Practice it
Choose the correct 〜てもいい form, or the right reply to a permission question.
＿＿＿に入れるのに最もよいものを選びなさい。
Choose the grammar pattern that best completes the sentence.
先生、写真を撮っ＿＿＿ですか。
Frequently asked questions
What does 〜てもいい mean?
It means 'it's okay to' or 'you may.' Take a verb's て-form and add もいい(です): ここに座ってもいいです = 'you may sit here.'
How do I ask 'May I…?' in Japanese?
Use 〜てもいいですか. For example, 写真を撮ってもいいですか = 'May I take a photo?' Drop the か and です for a casual 〜てもいい？
How do I answer a 〜てもいいですか question?
To allow it, say はい、どうぞ ('yes, go ahead'). To refuse politely, Japanese avoids a blunt no — say すみません、ちょっと… and trail off; the listener understands it means 'please don't.'
What's the difference between 〜てもいい and 〜てもかまいません?
Both grant permission. 〜てもいい is the everyday form; 〜てもかまいません ('I don't mind') sounds a touch more formal or reserved.
Where 〜てもいい fits
Shaky on this? Get these solid first
- 〜てください · N5 — 〜てください is the standard way to politely ask someone to do something ('please do…'). Learn the formation, the negative 〜ないでください, softer variations, and see clear examples.
- The て-form · N5 — The て-form is the gateway to dozens of Japanese grammar patterns. Learn the conjugation rules for every verb group, the famous song trick, and see clear examples.
Don't confuse it with
- 〜てください · N5 — 〜てください is the standard way to politely ask someone to do something ('please do…'). Learn the formation, the negative 〜ないでください, softer variations, and see clear examples.
Hear it in a real conversation
See this pattern used naturally in a real-situation dialogue:
More N5 grammar to explore
Keep going with related patterns at the same level:
- です — です is the polite 'to be': NOUN/な-adjective + です means 'is/are.' Learn the negative じゃありません, past でした, how です attaches to い-adjectives, and the plain だ.
- どんな — どんな means 'what kind of ~' and always sits before a noun: どんな音楽が好きですか. Learn the こ・そ・あ・ど set, どんな vs どう, and どんな〜でも ('any ~ at all').
- ある vs いる — Japanese has two existence verbs: いる for living things (people, animals) and ある for objects, plants, and events. Learn が, に, the negatives, and the classic mistakes.
- ごろ vs くらい — ごろ marks an approximate POINT in time (3時ごろ = around 3 o'clock), while くらい/ぐらい marks an approximate amount or duration (3時間くらい = about 3 hours).
- 〜ほうがいい — 〜ほうがいい gives advice: use the past (た) form for 'you should do X' (休んだほうがいい) and the ない-form for 'you'd better not' (行かないほうがいい). Learn the forms and nuance.
- じゃない — じゃない is the casual negative of nouns and な-adjectives: 学生じゃない ('not a student'). Learn じゃないです, ではない, the past じゃなかった, and the tag-question 〜じゃない？