Illustrators
- Johnh O'Connor 1
- Lauren O'Hara 1
- Hugh O'Neill 2
- Tom O'Reilly 4
- Paul O'Shea 1
- Graham Oakley 4
- Steve Oerding 1
- Angela Ogden 2
- H.A. Ogden 1
- Carol Ogilvie 1
- Sara Ogilvie 1
- James S. Ogilvy 1
- Ogle 5
- Richard B. Ogle 1
- Olinda 1
- Olive F. Openshaw 8
- Giulia Orecchia 2
- Jan Ormerod 3
- Jack Orr 2
- Stewart Orr 4
- D. Osborne 1
- B. Ostertag 1
- Paul Ott 1
- J.B. Oudry 1
- R.F. Outcault 2
- Ida Rentoul Outhwaite 5
- Denys Ovenden 1
- W.H. Overend 2
- T.J. Overnell 2
- Fiona Owen 1
- Ivan Owen 1
- W. Owen 1
- Will Owen 2
- Gail Owens 2
- Helen Oxenbury 8
- Oxley 1