Quinquagesima, in the Western Christian Churches, is the last pre-Lenten Sunday, being the Sunday before Ash Wednesday, and the first day of Carnival. It is also called Quinquagesima Sunday, Quinquagesimae, Estomihi, Shrove Sunday, Pork Sunday, or the Sunday next before Lent.

Pre-Lent begins the Christian time of preparation for Easter, in the three weeks before Lent. This period launches a campaign of catechesis, reflected in the liturgical readings. Its best-known feature is its concluding three-day festival, Carnival or Shrovetide.