Seiichi (written: , , , , , , , or ) is a masculine Japanese given name. Notable people with the name include:
*, Japanese karateka
*, Japanese cult member
*, Japanese politician
*, Japanese photographer
*, Japanese philosopher
*, Japanese art director
*, Japanese karateka
*, Japanese video game designer
*, Imperial Japanese Navy admiral
*, Japanese academic, historian and writer
*, Japanese golfer
*, Japanese politician
*, Japanese general
*, Japanese footballer
*, Japanese inventor
*, Japanese writer
*, Japanese photographer
*, Japanese footballer
*, Japanese poet and painter
*, Japanese footballer
*, Japanese politician
*, Japanese sport wrestler
*, Japanese politician
*, Japanese footballer
*, Japanese footballer
*, Japanese baseball player and soldier
*, Japanese aikidoka
*, Japanese philologist
*, Japanese figure skater
*, Japanese politician
*, Japanese handball player
*, Japanese photographer
*, Japanese actor
*, American musician
*, Japanese educator
*, Japanese scientist
*, Japanese baseball player
*, Japanese musician
{{given name
Japanese masculine given names