HSI

• Croatian Syrmian Initiative, a political party in Serbia ({{langx|hr|Hrvatska srijemska inicijativa|links=no}})
• Hispanic-serving institution, an American college designation
• Homeland Security Investigations, an American law enforcement agency
• Humane Society International, an animal welfare organization

• HSI color space, in computing
• Heterosubtypic immunity, in medicine
• High Speed Interconnect, a computer chip
• Horizontal shaft impactor, a rock crusher
• Horizontal situation indicator, an aircraft instrument
• Hurricane Severity Index
• Hyperspectral imaging

• HSI (track team)
• Croatian World Games ({{langx|hr|Hrvatske svjetske igre|links=no}}), multi-sport international event
• Icelandic Handball Association ({{langx|is|Handknattleikssamband Íslands|links=no}}, {{lang|is|HSÍ}})

• Hsi (surname), various Chinese surnames, romanized {{lang|zh-Latn|Xi}} in Pinyin
• Hang Seng Index, a stock market index
• Hastings Municipal Airport, Nebraska, United States
• Billboard Hot 100, a chart with the shortcut "HSI"

• HS1 (disambiguation) ('HS' and the digit '1')
• Xi (disambiguation) — {{lang|zh-Latn|Xi}} and {{lang|zh-Latn|Hsi}} are different transliterations of the same sound in Chinese

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