Japanese Family Relationship Terms

Father's father

Ojii-san (お祖父さん)

Japanese doesn't distinguish paternal vs maternal grandparents in everyday speech.

Father's mother

Obaa-san (お祖母さん)

Mother's father

Ojii-san (お祖父さん)

Mother's mother

Obaa-san (お祖母さん)

Father

Otou-san (お父さん)

Mother

Okaa-san (お母さん)

Father's older brother

Oji-san (伯父さん)

Japanese distinguishes aunts/uncles by whether they're older or younger than your parent, not by which side of the family they're on.

Father's younger brother

Oji-san (叔父さん)

Father's sister

Oba-san (伯母さん/叔母さん)

Mother's older brother

Oji-san (伯父さん)

Mother's younger brother

Oji-san (叔父さん)

Mother's sister

Oba-san (伯母さん/叔母さん)

Father's older brother's wife

Oba-san (伯母さん)

Father's younger brother's wife

Oba-san (叔母さん)

Mother's brother's wife

Oba-san (伯母さん/叔母さん)

Father's sister's husband

Oji-san (伯父さん/叔父さん)

Mother's sister's husband

Oji-san (伯父さん/叔父さん)

Older brother

Onii-san (お兄さん)

Younger brother

Otouto (弟)

Older sister

Onee-san (お姉さん)

Younger sister

Imouto (妹)

Father's brother's son

Itoko (いとこ)

One gender-neutral word covers every kind of cousin, with no distinction by side of family, age or gender, unlike Chinese or the Indian languages here.

Father's brother's daughter

Itoko (いとこ)

Father's sister's son

Itoko (いとこ)

Father's sister's daughter

Itoko (いとこ)

Mother's brother's son

Itoko (いとこ)

Mother's brother's daughter

Itoko (いとこ)

Mother's sister's son

Itoko (いとこ)

Mother's sister's daughter

Itoko (いとこ)

Son

Musuko (息子)

Daughter

Musume (娘)

Grandson

Mago-musuko (孫息子)

'Mago' alone covers any grandchild.

Granddaughter

Mago-musume (孫娘)

Son-in-law

Muko (婿)

Daughter-in-law

Yome (嫁)

Brother's son

Oi (甥)

No distinction between a brother's or a sister's son.

Sister's son

Oi (甥)

Brother's daughter

Mei (姪)

Sister's daughter

Mei (姪)

Husband

Otto (夫)

Wife

Tsuma (妻)

Spouse's father

Gifu (義父)

Spouse's mother

Gibo (義母)

Husband's older brother

Gikei (義兄)

Japanese in-law terms for spouse's siblings and siblings' spouses share the same 義 (gi-, 'in-law') system, split only by relative age.

Husband's younger brother

Gitei (義弟)

Husband's sister

Gishi (義姉) / Gimai (義妹)

Wife's brother

Gikei (義兄) / Gitei (義弟)

Wife's sister

Gishi (義姉) / Gimai (義妹)

Brother's wife

Gishi (義姉, if older) / Gimai (義妹, if younger)

Sister's husband

Gikei (義兄, if older) / Gitei (義弟, if younger)