Horii (written: 堀井) is a Japanese surname. Notable people with the surname include:
Gakuya Horii (堀井 岳也, born 1975), Japanese footballer
Manabu Horii (堀井 学, born 1972), Japanese speed skater and politician
Ryuji Horii (堀井 利有司, born 1974), Japanese swimmer
Saori Horii (堀井 沙織, born 1984), Japanese gravure idol
Tomitarō Horii (堀井 富太郎, 1890–1942), Japanese general
Yoshiharu Horii (堀井 美晴, born 1953), Japanese footballer
Yuji Horii (堀井 雄二, born 1954), Japanese video game designer