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