〜てもいい: Asking and Giving Permission in Japanese
What it means
〜てもいい literally stacks two pieces: the て-form (the connective "and/doing…") plus もいい ("is also good / is fine"). Together they mean the action is permitted — "it's okay to do it," "you may do it." Drop the です for casual speech, keep it for polite.
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.
How to form it
Start from the verb's て-form, then attach もいい(です). The conjugation never changes for the verb — only もいい moves between polite and casual.
| 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 permission: 〜てもいいですか
Add か to turn the statement into a request for permission — 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?
Natural replies
When you say yes, the warm, common reply is はい、どうぞ ("yes, go ahead"). To say no politely, Japanese rarely uses a blunt "no" — a soft すみません、ちょっと… ("sorry, that's a little…") trails off and the listener understands.
「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.
Casual 〜てもいい and the formal 〜てもかまいません
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.
For a touch more formality (or to sound a little more reserved), swap いい for かまいません ("I don't mind / it doesn't matter"). The meaning is the same — permission — but 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…'
The opposite ideas (in brief)
Two related patterns sit on the "no" side of permission. You don't need them in depth yet, but it helps to recognize them:
- 〜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.
Common mistakes
- 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.
Quick recap
- 〜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).
Your turn
Choose the correct 〜てもいい form, or the right reply to a permission question.
Start the 5-question drill →Take the full N5 〜てもいい drill →
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.