Shrove Tuesday or Pancake Day is the day before Ash Wednesday (the first day of Lent), observed in many Christian countries through participating in confession and absolution, the ritual burning of the previous year's Holy Week palms, finalizing one's Lenten sacrifice, as well as eating pancakes and other sweets.

Shrove Tuesday is observed by many Christians, including Anglicans, Lutherans, Methodists and Roman Catholics, who "make a special point of self-examination, of considering what wrongs they need to repent, and what amendments of life or areas of spiritual growth they especially need to ask God's help in dealing with." This moveable feast is determined by Easter. The expression "Shrove Tuesday" comes from the word shrive, meaning "absolve".

As this is the last day of the Christian liturgical season historically known as Shrovetide, before the penitential season of Lent, related popular practices, such as indulging in food that one might give up as their Lenten sacrifice for the upcoming forty days, are associated with Shrove Tuesday celebrations. The term Mardi Gras is French for "Fat Tuesday", referring to the practice of the last night of eating richer, fatty foods before the ritual fasting of the Lenten season, which begins on Ash Wednesday. Many Christian congregations thus observe the day through eating pancakes or, more specifically, the holding of pancake breakfasts, as well as the ringing of church bells to remind people to repent of their sins before the start of Lent. On Shrove Tuesday, churches also burn the palms distributed during the previous year's Palm Sunday liturgies to make the ashes used during the services held on the very next day, Ash Wednesday.

In some Christian countries, especially those where the day is called Mardi Gras or a translation thereof, it is a carnival day, the last day of "fat eating" or "gorging" before the fasting period of Lent.