HHS
- Hadleigh High School
- Hall High School (Connecticut)
- Hall High School (Illinois)
- Halton High School
- Hamilton Health Sciences
- Hamilton High School (disambiguation)
- Hampshire High School (Illinois)
- Hampshire High School (West Virginia)
- Hanover High School (New Hampshire)
- Hardaway High School
- Hardee High School
- Hardin High School (Montana)
- Hardin High School (Texas)
- Hardin High School (disambiguation)
- Harlingen High School
- Harmony High School
- Harrisburg High School (Arkansas)
- Harrisburg High School (Oregon)
- Harrison High School (Arkansas)
- Harrison High School (New Jersey)
- Harrison High School (New York)
- Harrisonburg High School (Virginia)
- Harriton High School
- Harte Hanks
- Hartsville High School
- Harvard High School (Illinois)
- Hastings High School (disambiguation)
- Havana High School
- Haverford High School
- Haverhill High School
- Havre De Grace High School
- Hayward High School (Wisconsin)
- Healdsburg High School
- Heartlands High School, London
- Helena High School (Alabama)
- Hempfield High School
- Hempstead High School (Dubuque, Iowa)
- Henderson High School (Auckland)
- Henderson High School (Pennsylvania)
- Hendersonville High School (Tennessee)
- Hereford High School (Parkton, Maryland)
- Hereward House School
- Heritage High School (disambiguation)
- Hermiston High School
- Hernando High School (Florida)
- Herndon High School
- Herriman High School
- Herrin High School
- Hibriten High School
- Hickman High School
- Highland High School (Pocatello, Idaho)
- Highland High School (disambiguation)
- Hightower High School
- Hillsboro High School (disambiguation)
- Hillsborough High School (New Jersey)
- Hillsborough High School (Tampa, Florida)
- Hillside High School (Durham, North Carolina)
- Hilltop High School (Whitecourt)
- Hillwood High School
- Hirschi High School
- Hobbs High School
- Holcomb High School
- Holland High School (disambiguation)
- Holliston High School
- Holly High School
- Holroyd High School
- Holyoke High School
- Homestead High School (Cupertino, California)
- Homewood High School
- Hornbeck High School
- Hortonville High School
- Howell High School (Howell, Michigan)
- Hoyeraal-Hreidarsson syndrome
- Hubbard High School (Ohio)
- Hudson High School (Massachusetts)
- Hudson High School (Ohio)
- Hudsonville High School
- Hueneme High School
- Huffman High School
- Hughes High School
- Huguenot Street Historic District
- Humble High School
- Huntingtown High School
- Huntsville High School (disambiguation)
- Huron High School (Ann Arbor, Michigan)
- Hutchings High School
- Hutchinson High School (Kansas)
- Hutchinson High School (Minnesota)
- Hyperosmolar hyperglycemic state
- Hénon-Heiles System
- Stockholm School of Economics
- The Hague University of Applied Sciences
- United States Department of Health and Human Services