I've never heard someone say "ii yo". Is "ii yo" acceptable? And "ii zo"? In particular, in casual masculine speech.

  • 1
    Happens all the time. You should try hearing more things (^^)
    – Sjiveru
    Sep 13, 2017 at 2:34

2 Answers 2


In English, it would be similar to casually saying "yeah, sure!".


  • Can I borrow your pen?
  • Yeah, sure!

  • ペン貸してくれる?
  • いいよ

いいぞ, is also correct but it's less standard. I never heard people actually use that in my experience. But people talk in all kinds of weird ways. Imagine someone saying the following in English: Yeah bruh

It's not standard but some people actually talk like that so culturally speaking, it's not wrong.


いいよ (ii yo) is a casual way to say "okay", "no problem", "I'll do it", etc.

  • It is not acceptable in formal/business settings. Don't use it.
  • It is commonly and actively used among friends, regardless of sex.
  • It is not common in some dialects where other expressions are used by default. Kansai-ben speakers would use ええよ or ええで.

いいぞ can be heard when cheering sport players (sounds like "way to go!"), but otherwise uncommon in the real-world spoken Japanese. You can say this to someone who is really inferior to or close to you (for instance your children), but it tends to sound "bossy".

  • Is it acceptable in formal/business settings? May I use it?
    – Kommi
    Sep 13, 2017 at 5:32
  • Usually, both expressions doesn't fit to business/formal settings. I'd say どうぞ in those situation.
    – user19858
    Sep 13, 2017 at 5:41
  • いいぞ can be heard when things you are looking are coming along not only when spectating sport games. いいぞ as acceptance can makes sense but it would be very rare and sounds quite arrogant/condescending.
    – user19858
    Sep 13, 2017 at 5:46

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