Languages › Japanese Gomennasai Versus Sumimasen in Japanese Share Flipboard Email Print RunPhoto/Getty Images Japanese Essential Japanese Vocabulary History & Culture Japanese Grammar By Namiko Abe Japanese Language Expert B.A., Kwansei Gakuin University Namiko Abe is a Japanese language teacher and translator, as well as a Japanese calligraphy expert. She has been a freelance writer for nearly 20 years. our editorial process Namiko Abe Updated May 24, 2018 Both "Gomennasai" and "Sumimasen" are used when you have made a mistake or inconvenienced someone. "Sumimasen" is also used when expressing a feeling of gratitude, but "Gomennasai" cannot be used in such situations. For the most part, it comes down to a matter of personal preference whether to use either "Sumimasen （すみません）" or "Gomennasai （ごめんなさい）", but there are a few subtleties to be aware of. "Sumimasen" is a little more formal than "Gomennasai."When you apologize to the higher or the senior, "Sumimasen" is used in general.Among the family members or close friends, it is common to use "Gomennasai." "Gomen ne" or "Gomen" can be used in a more casual case.Older people tend to use "Sumimasen" more than younger people. "Gomennasai" can be used when apologizing to someone with whom you have a close relationship. But when speaking with superiors or people with whom one is not very close, "Sumimasen" or "Moushiwake arimasen" are used instead, since "Gomennasi" can have a childish ring to it.