John Wycliffe (also spelled Wyclif, Wycliff, Wiclef, Wicliffe, Wickliffe; c. 1331 – 31 December 1384) is an English Scholastic philosopher, theologian, lay preacher, translator, reformer and university teacher at Oxford in England.

He is an influential dissident in the Roman Catholic Church during the fourteenth century.

His followers are known as Lollards, a somewhat rebellious movement, which preaches anticlerical and biblically-centered reforms.

The Lollard movement is a precursor to the Protestant Reformation.

He has been characterized as the evening star of scholasticism and the Morning Star of the Reformation.

He is one of the earliest opponents of papal authority over secular power.

In assessing Wycliffe’s historical role, Lacey Baldwin Smith argues that Wycliffe expounded three doctrines that the established church recognized as major threats.

First was his emphasis upon an individual's interpretation of the Bible as the best guide to a moral life, as opposed to the Church’s emphasis on receiving its sacraments as the only way to salvation.

Second he insisted that holiness of an individual was more important than official office; that is, a truly pious person was morally superior to a wicked ordained cleric.

Wycliffe challenges the privileged status of the clergy, which was central to their powerful role in England.

Finally he attacks the exorbitant luxury and pomp of the churches and their ceremonies.

Wycliffe is also an early advocate for translation of the Bible into the common language.

He completes his translation directly from the Vulgate into vernacular English in the year 1382, now known as Wycliffe's Bible.

It is probable that he personally translated the Gospels of Matthew, Mark, Luke, and John; and it is possible he translated the entire New Testament, while his associates translated the Old Testament.

Wycliffe's Bible appears to have been completed by 1384, with additional updated versions being done by Wycliffe's assistant John Purvey and others in 1388 and 1395.