Yoshii (written: 吉井) is a Japanese surname. Notable people with the surname include:
Hidekatsu Yoshii (吉井 英勝, born 1942), Japanese politician
Yoshii Isamu (吉井 勇, 1886–1960), Japanese poet and playwright
Kanae Yoshii (吉井 香奈恵, born 1993), Japanese idol, singer and actress
Kosuke Yoshii (吉井 孝輔, born 1986), Japanese footballer
Manami Yoshii (吉井 愛美, born 1981), Japanese AV actress
Masato Yoshii (吉井 理人, born 1965), Japanese baseball player
Naoto Yoshii (吉井 直人, born 1987), Japanese footballer
Rei Yoshii (吉井 怜, born 1982), Japanese actress
Sayuri Yoshii (吉井 小百合, born 1984), Japanese speed skater
