"Un jour, un enfant" (French pronunciation: ​[œ̃ ʒuʁ œ̃n‿ɑ̃fɑ̃]; "A Day, a Child") is one of four winning songs in the Eurovision Song Contest 1969, this one being sung in French by Frida Boccara representing France. The other three winners were Salomé representing Spain with "Vivo cantando", Lulu representing the United Kingdom with "Boom Bang-a-Bang" and Lenny Kuhr representing the Netherlands with "De troubadour".

The song was performed fourteenth on the night, following Germany's Siw Malmkvist with "Primaballerina" and preceding Portugal's Simone de Oliveira with "Desfolhada portuguesa". At the close of voting, it had received 18 points, placing equal first in a field of 16.

The song is a classical ballad, describing the wonders of the world as seen by a child. Boccara recorded the song in five languages, French, English (as "Through the Eyes of a Child"), German ("Es schlägt ein Herz für dich", translated: "A Heart Beats for You"), Spanish ("Un día, un niño", translated: "A Day, a Child") and Italian ("Canzone di un amore perduto", translated: "Song of a Lost Love").

The song was succeeded as (joint) contest winner in 1970 by Dana singing "All Kinds of Everything" for Ireland. It was succeeded as French representative that year by Guy Bonnet with "Marie-Blanche".