In antiquity, a châtelet was a little castle or fortress, wherein the chatelain, or governor lodged.

Now, the term may refer to:

• The city of Châtelet, Belgium.
• Émilie du Châtelet, the 18th century French mathematician, physicist, and author.
• François Châtelet (d. 1985), French historian of political philosophy.
• Place du Châtelet, a public square in Paris, on the Right Bank of the Seine on the border of the 1st and 4th arrondissements.
• Théâtre du Châtelet, a theatre in Paris
• Châtelet, a Metro station in Paris, located near the Place du Châtelet
• Châtelet - Les Halles, the central commmuter train station in Paris, attached to both the Châtelet and Les Halles metro stations.