The Infancy Gospel of Thomas (also known as the Infancy of Jesus or Childhood of Jesus, the Paidika tou Iesou or Paidika (Greek), and abbreviated as Inf. Gos. Thom. or IGT) is an apocryphal gospel about the childhood of Jesus. Together with the Gospel of James, it was one of the earliest and most influential sources detailing the activities and life of the young Jesus, although neither are included in the New Testament canon. Its creation is generally dated to the second century. The oldest extant fragmentary writing dates to the fourth or fifth century; Latin and Syriac attestations to a short form exist from the fifth or sixth century; and an 11th-century manuscript in Greek (Codex Sabaiticus) contains the earliest extant long form of the work. Variants flourished that expanded the work by combining it with other stories in larger works and anthologies; the Gospel of Pseudo-Matthew is one example that proved popular in the Latin-speaking Western Church during the Middle Ages.

The Infancy Gospel of Thomas depicts a young Jesus in full possession of divine power who is already dispensing wisdom with authority, even at an early age. It includes several miracles that spread widely and appear in other sources, such as Jesus transforming clay sparrows into live sparrows. Jesus sometimes wields his power in a capricious way, such as where young Jesus curses and kills those who cross him. While the Jesus depicted in this gospel can be an "enfant terrible", he balances this with performing miracles and healing, as well.

The author of the work is not known. Some versions include a pseudepigraphal attribution to "Thomas the Israelite", which might be a reference to Thomas the Apostle, but this attribution appears to date to the medieval period and is only in some manuscripts. The work varies greatly in style from the canonical gospels. The Infancy Gospel of Thomas ends with its account of Jesus in the temple at age 12, a story originally from the Gospel of Luke.

Most scholars suggest that the Infancy Gospel of Thomas dates to the mid-to-late second century. The work and the stories within it appear to have been popular, with a wide geographical spread and many translations to new languages. At least some period of oral transmission of the source material is generally believed to have occurred, either wholly or as several different stories. Eventually it was transcribed, and over time redacted and adapted. The earliest evidence of the text comes from the late second century. Two 2nd-century documents, the Epistle of the Apostles (by an unknown author) and Against Heresies (by Irenaeus), refer to a story of Jesus's tutor telling him, "Say alpha," and Jesus replying, "First tell me what is beta, and I can tell you what alpha is." Irenaeus's work is dated to around 180 CE. Irenaeus did not give a name to the book he quoted from, but he condemned it as spurious and heretical. An early form of the infancy gospel circulating would make sense for the era. There are further references that seem to indicate the spread of the stories; the Syriac form of the third-century Acts of Thomas contains a possible mention. In the fourth century, Epiphanius of Salamis's Panarion quotes Jesus's childhood miracles approvingly, while John Chrysostom condemns these stories of childhood miracles as false.

The author of the gospel is unknown. The author was probably a gentile Christian, as the work displays no knowledge of Judaism. The author was educated and knew some rare words in an era when literacy was uncommon, but wrote in a style that was overall simple and readable. The geographic origin of the author is also unknown, leaving scholars with little more than guesses. Jan Bremmer weakly suggests Alexandria in Roman Egypt as plausible, but cautions that nothing can be said with certainty on the matter. Tony Burke suggests it was a place where the Gospel of Luke was held in high regard: perhaps Asia Minor (modern Turkey) or Antioch in Roman Syria. Others such as Sever Voicu have suggested Roman Palestine. J.R.C. Cousland cautions that the safest, if least specific, suggestion is somewhere in the Greek-speaking Eastern Roman Empire.

The early versions of the work were anonymous. No author is indicated in the earliest surviving manuscripts (Latin, Syriac, Georgian, Ethiopic). In some later manuscripts dating from the Middle Ages, the gospel opens with a prologue where "Thomas the Israelite" introduces himself as the author, but with no further explanation. It is possible that this was meant to hint that the author was Judas Thomas, known as Thomas the Apostle, thought by some Christians to be a brother of Jesus and thus familiar with young Jesus's activities. The Latin version closes with an epilogue where the author claims to have been an eyewitness who witnessed these events personally, another claim that seems to have been added centuries after the original story's circulation. Two other figures have been attributed claims of authorship: John the Evangelist in some early Latin translations, and James, brother of Jesus in some Greek versions.

The text describes the life of the child Jesus from the ages of five to twelve, with fanciful, and sometimes malevolent, supernatural events. He is presented as a precocious child who starts his education early. This summary uses the order in the Greek A recension.

A five-year old Jesus is playing in the mud after rain near a river. He organizes the water into pools. With a single word, he miraculously cleanses the water. He then crafts 12 sparrows from the clay while playing with other children. A Jew, displeased with seeing children work on the Sabbath, reports this to Jesus's father Joseph. Jesus gives life to the sparrows and they fly off. Another boy, the son of Annas, breaks the pools Jesus made, letting their water drain out. Jesus pronounces a curse upon the boy, and he instantly withers. The parents ineffectively complain to Joseph.