- O Would I were a boy again
- O'er Moor and Fen
- O, the sight entrancing
- Ode for Music
- Odes
- Odyssey
- Of a Precise Taylor
- Of Beauty
- Of Love and Lust
- Of Personal Merit
- Of Praise
- Oh Come All Ye Faithful
- Old Mortality
- Oliver Twist
- Oliver Twist
- Olney Hymns
- Omni
- On Becoming
- On Being Idle
- On Being Shy
- On Boundaries
- On Dress
- On Friendship
- On Heroes and Hero Worship
- On Liberty
- On Love
- On Marriage, The Delight of Muses
- On Peace of Mind, Moral Essays
- On Prejudice
- On Sensibility
- On Taking Leave of
- On the Collar of a Dog
- On the Earl of Southampton
- On the good of marriage
- On the Knowledge of Character
- On the Late Massacre in Piedmont
- On the Nature of Things
- On the pulse of Morning
- On the Study of Words
- On the sublime and Beautiful
- One-Way Street
- Opus Maius
- Ordinary People
- Orestes
- Organon of Medicine
- Orthodoxy
- Othello
- Our Master
- Our Mutual Friend
- Outermost House
- Ovid
- Oxford Dictionary of Modern Quotations