Seishi YAMAGUCHI (November 3, 1901 - March 26, 1994) is a haiku poet (a Japanese poem in seventeen syllables having a 5-7-5 syllabic form and traditionally containing a reference to the seasons) from Kyoto City, Kyoto Prefecture.
山口誓子（やまぐちせいし、1901年11月3日-1994年3月26日）は京都府京都市出身の俳人。