Diminutive of Oliver or Olivia, from Latin oliva meaning 'olive tree'.
Olly is a cheerful, bouncing diminutive of Oliver, a name whose etymology has been pleasantly contested for centuries. The most romantic origin links it to the Latin *olivarius* (olive tree), with the olive branch carrying its ancient burden of peace and prosperity. A competing theory connects it to the Old Norse name Óleifr, meaning 'ancestor's relic,' which traveled south with Viking settlers.
Whatever the root, Oliver arrived in England with the Normans and was common enough by the medieval period to make it into the Oxford English Dictionary of medieval given names. Oliver gained immense literary prestige through Charles Dickens, whose 1838 novel *Oliver Twist* gave the world a protagonist whose hungry innocence — 'Please, sir, I want some more' — became one of the most quoted lines in Victorian fiction. The name survived that association and eventually transcended it, riding the early twentieth century's wave of Edwardian revival names before becoming one of the most popular boys' names in the English-speaking world in the 2010s.
Olly, as the diminutive, captures all that warmth in a softer, more playful package. In British culture especially, Olly has an irrepressible friendliness — it is the name you give a puppy or a best mate, a rugby captain or a children's TV presenter. Olly Murs, the British pop singer, brought it considerable contemporary visibility. Used as a standalone name rather than a nickname, Olly signals parents who want the full warmth of Oliver without the formality, preferring a name that greets every room like it already knows everyone in it.