Oscar Wilde was born at 21 Westland Row, Dublin (now home of the Oscar Wilde Centre, Trinity College, Dublin) the second of three children born to Sir William Wilde and Jane Francesca Wilde, two years behind William ("Willie"). Jane Wilde, under the pseudonym "Speranza" (the Italian word for 'Hope'), wrote poetry for the revolutionary Young Irelanders in 1848 and was a life-long Irish nationalist. She read the Young Irelanders' poetry to Oscar and Willie, inculcating a love of these poets in her sons. Lady Wilde's interest in the neo-classical revival showed in the paintings and busts of ancient Greece and Rome in her home. William Wilde was Ireland's leading oto-ophthalmologic (ear and eye) surgeon and was knighted in 1864 for his services as medical adviser and assistant commissioner to the censuses of Ireland. He also wrote books about Irish archaeology and peasant folklore. A renowned philanthropist, his dispensary for the care of the city's poor at the rear of Trinity College, Dublin, was the forerunner of the Dublin Eye and Ear Hospital, now located at Adelaide Road.

In addition to his children with his wife, Sir William Wilde was the father of three children born out of wedlock before his marriage: Henry Wilson, born in 1838, and Emily and Mary Wilde, born in 1847 and 1849, respectively, of different parentage to Henry. Sir William acknowledged paternity of his illegitimate children and provided for their education, but they were reared by his relatives rather than with his wife and legitimate children.

In 1855, the family moved to No. 1 Merrion Square, where Wilde's sister, Isola, was born the following year. The Wildes' new home was larger and, with both his parents' sociality and success soon became a "unique medical and cultural milieu"; guests at their salon included Sheridan le Fanu, Charles Lever, George Petrie, Isaac Butt, William Rowan Hamilton and Samuel Ferguson.

Until he was nine, Oscar Wilde was educated at home, where a French bonne and a German governess taught him their languages. He then attended Portora Royal School in Enniskillen, County Fermanagh. Until his early twenties, Wilde summered at the villa his father built in Moytura, County Mayo. There the young Wilde and his brother Willie played with George Moore.

Isola died aged eight of meningitis. Wilde's poem Requiescat is dedicated to her memory:

"Tread lightly, she is nearUnder the snowSpeak gently, she can hearthe daisies grow"

Trinity College, Dublin

Wilde left Portora with a royal scholarship to read classics at Trinity College, Dublin, from 1871 to 1874, sharing rooms with his older brother Willie Wilde. Trinity, one of the leading classical schools, set him with scholars such as R.Y. Tyrell, Arthur Palmer, Edward Dowden and his tutor, J.P. Mahaffy who inspired his interest in Greek literature. As a student Wilde worked with Mahaffy on the latter's book Social Life in Greece. Wilde, despite later reservations, called Mahaffy "my first and best teacher" and "the scholar who showed me how to love Greek things". For his part Mahaffy boasted of having created Wilde; later, he would name him "the only blot on my tutorship".

The University Philosophical Society also provided an education, discussing intellectual and artistic subjects such as Rosetti and Swinburne weekly. Wilde quickly became an established member — the members' suggestion book for 1874 contains two pages of banter (sportingly) mocking Wilde's emergent aestheticism. He presented a paper entitled "Aesthetic Morality". At Trinity, Wilde established himself as an outstanding student: he came first in his class in his first year, won a scholarship by competitive examination in his second, and then, in his finals, won the Berkeley Gold Medal, the University's highest academic award. He was encouraged to compete for a demyship to Magdalen College, Oxford — which he won easily, having already studied Greek for over nine years.

Magdalen College, Oxford

At Magdalen he read Greats from 1874 to 1878, and from there he applied to join the Oxford Union, but failed to be elected.

Attracted by its dress, secrecy and ritual, Wilde petitioned the Apollo Masonic Lodge at Oxford, and was soon raised to the "Sublime Degree of Master Mason". During a resurgent interest in Freemasonry in his third year, he commented he "would be awfully sorry to give it up if I secede from the Protestant Heresy". He was deeply considering converting to Catholicism, discussing the possibility with clergy several times. In 1877, Wilde was left speechless after an audience with Pope Pius IX in Rome. He eagerly read Cardinal Newman's books, and became more serious in 1878, when he met the Reverend Sebastian Bowden, a priest in the Brompton Oratory who had received some high profile converts. Neither his father, who threatened to cut off his funds, nor Mahaffy thought much of the plan; but mostly Wilde, the supreme individualist, baulked at the last minute from pledging himself to any formal creed. On the appointed day of his baptism, Fr Bowden received a bunch of altar lilies instead. Wilde retained a lifelong interest in Catholic theology and liturgy.

While at Magdalen College, Wilde became particularly well known for his role in the aesthetic and decadent movements. He wore his hair long, openly scorned "manly" sports though he occasionally boxed, and decorated his rooms with peacock feathers, lilies, sunflowers, blue china and other objets d'art, once remarking to friends whom he entertained lavishly, "I find it harder and harder every day to live up to my blue china." The line quickly became famous, accepted as a slogan by aesthetes but used against them by critics who sensed in it a terrible vacuousness. Some elements disdained the aesthetes, but their languishing attitudes and showy costumes became a recognised pose. Wilde was once physically attacked by a group of four fellow students, and dealt with them single-handedly, surprising critics. By his third year Wilde had truly begun to create himself and his myth, and saw his learning developing in much larger ways than merely the prescribed texts. This attitude resulted in him being rusticated for one term, when he nonchalantly returned to college late from a trip to Greece with Prof. Mahaffy.

Wilde did not meet Professor Walter Pater until his third year, but had been enthralled by his Studies in the History of the Renaissance, published during Wilde's final year in Trinity. Pater argued that man's sensibility to beauty should be refined above all else, and that each moment should be felt to its fullest extent. Years later in De Profundis, Wilde called Pater's Studies... "that book that has had such a strange influence over my life". He learned tracts of the book by heart, and carried it with him on travels in later years.

Pater gave Wilde his sense of almost flippant devotion to art, though it was Professor John Ruskin who gave him a purpose for it. Ruskin despaired at the self-validating aestheticism of Pater; for him the importance of art lay in its potential for the betterment of society. He too admired beauty, but it must be allied with and applied to moral good. When Wilde eagerly attended his lecture series The Aesthetic and Mathematic Schools of Art in Florence, he learned about aesthetics as simply the non-mathematical elements of painting. Despite being given to neither early rising nor manual labour, Wilde volunteered for Ruskin's project to convert a swampy country lane into a smart road neatly edged with flowers.

Wilde won the 1878 Newdigate Prize for his poem Ravenna, which reflected on his visit there the year before, and he duly read it at Encaenia. In November 1878, he graduated with a rare double first in his B.A. of Classical Moderations and Literae Humaniores (Greats). Wilde wrote a friend, "The dons are beyond words — the Bad Boy doing so well in the end!"