Last names starting with "O"
- Class of 1954 Donald O'brien
- Class of 1975 James O'Brien
- Class of 1970 Matt OCallaghan
- Class of 1982 Gerald OConnell
- Class of 1973 Sylvester Odell
- Class of 1940 John OMalley
- Class of 1974 Dave Omastiak
- Mike Oneal
- Peter ONeal
- Class of 1953 Frank ONeil
- Class of 1953 Frances ONeill
- Class of 1967 Thomas Osborne
- Class of 1952 Tom Otoole
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