L
- Lagan College, Belfast
- La Salle Boys' School, Belfast
- Larne High School, Larne, County Antrim
- Laurelhill Community College, Lisburn, County Antrim
- Limavady High School, Limavady, County Londonderry
- Lismore Comprehensive School, Craigavon, County Armagh
- Lisnagarvey High School, Lisburn, County Antrim
- Lisnasharragh High School, Belfast
- Lisnaskea High School, Lisnaskea, County Fermanagh
- Lisneal College, Derry
- Little Flower Girls' School, Belfast
- Lurgan Junior High School, Lurgan, County Armagh
- Lumen Christi College, Derry, County Londonderry
Loreto college Coleraine
Read more about this topic: List Of Secondary Schools In Northern Ireland