HTO may refer to:
Places HTO Park a beach in Toronto, Ontario, Canada
Transportation East Hampton Airport, in New York, United States Hightown railway station, in England
Science and technology High tibial osteotomy High Temperature Oxide Hohmann transfer orbit Holocene thermal optimum Waco HTO, an American biplane Partially tritiated water
Business Hostile takeover Hellenic Tourist Organisation
Other uses Haupttreuhandstelle Ost, a Nazi state institution in occupied Poland Minica Huitoto, spoken in Colombia and Peru OTE, a Greek telecommunications company