1920s
- 1920 Castleknock College
- 1921 Castleknock College
- 1922 Castleknock College
- 1923 Blackrock College
- 1924 Castleknock College
- 1925 Belvedere College
- 1926 Castleknock College
- 1927 Blackrock College
- 1928 Castleknock College
- 1929 Belvedere College
Read more about this topic: Leinster Schools Junior Cup