"Mary, Did You Know?" is a Christmas song addressing Mary, mother of Jesus, with lyrics written by Mark Lowry in 1984, and music written by Buddy Greene in 1991. It was originally recorded by Christian recording artist Michael English on his self-titled debut solo album in 1991. At the time, English and Lowry were members of the Gaither Vocal Band, and Greene was touring with them.^[1] The song reached number six on CCM Magazine's Adult Contemporary Chart.^[2] In 1993, the second singer (and first secular artist) to record the song was Country singer Kathy Mattea on her album Good News, which won the Grammy Award for Best Southern, Country or Bluegrass Gospel Album.^[3] Lowry would record the song several times himself, most notably with the Gaither Vocal Band on their 1998 Christmas album, Still the Greatest Story Ever Told.

The song has since gone on to become a modern Christmas classic, recorded by hundreds of artists over the years, across multiple genres.^[1] Several recordings have reached the top ten in various Billboard charts. The song encourages contemplation of the relationship between Mary and her son, although some religious commentators have criticized the lyrics.

"Mary, Did You Know?" was originally released in the key of E♭ minor, with a tempo of 53 beats per minute in ⁴
₄ meter, based around a chord progression of E♭m–D♭–A♭m7–B♭7sus4–B♭7.^[4] The lyrics evolved from a series of questions that Lowry scripted for a Christmas program at his church:

I just tried to put into words the unfathomable. I started thinking of the questions I would have for her if I were to sit down & have coffee with Mary. You know, "What was it like raising God?" "What did you know?" "What didn't you know?"^[1]

None of the questions are answered in the song. Instead, the lyrics poetically invite the listener to contemplate the relationship between Mary and her newborn divine son,^[5] even if her faith and awareness did not yet include the details of what would unfold.^[6]

The text has received both praise for reflecting the love of God, as well as criticism for perceived ambiguity or lack of theological depth.^[7][5][8] Baptist theologian Michael Frost suggested that it was the "most sexist Christmas song ever written... It treats her like a clueless child... Could you imagine a song asking Abraham 17 times if he knew he'd be the father of a great nation?"^[9] Robert McTeigue and Michelle Arnold, both Roman Catholic commentators, have questioned a particular line of text ("This Child that you delivered will soon deliver you") that might confuse or challenge the belief that Mary herself was conceived without sin.^[5][6][8] On the other hand the Roman Catholic author Karl Erickson implored people to praise Mary, Did You Know? as a "beautiful expression of God’s love for all of us" and responded to criticism of the piece, stating that "Mary, Did You Know is a song and not a theological essay. Even as simple Christmas music, however, it does a fine job conveying the beauty and profound mystery of the Incarnation. Yes, there is some poetic license taken within the lyrics, but much less than is taken within innumerable other songs we are asked to sing regularly—Sing a New Church, for example."^[7] Lutheran clergyman Timothy Koch states that criticism of the song is unwarranted because Mary, Did You Know? is simply poetry using rhetorical questions and that it is "actually communicating to the singer and hearer the truths about Jesus", including doctrines of salvation, homoousious, and the theotokos.^[10]

In 2017, Toronto-based theologian Jennifer Henry wrote new lyrics that address the criticisms and echo Mary's words from the biblical Magnificat.^[11] These new lyrics have begun to spread in religious settings.^{[12][13][14][15][16][17]}

The song was used as the basis for a stage musical, written by David Guthrie and Bruce Greer and also titled Mary, Did You Know?, which won the 1999 Gospel Music Association Dove Award for Musical of the Year.^[18]