Kajsa is a female given name of Swedish origin, derived from the Old Norse word 'kæðisa', meaning "of noble descent". It was introduced to Sweden through Norse influence and has since become popular in Sweden and other Nordic countries, though it is less common elsewhere. In English-speaking regions, Kajsa may be anglicized as Kasia or Cajsa. The name gained notable recognition in the Swedish literary world through Selma Lagerlöf's character Kajsa Warg in her novel "Jerusalemsflyktarna" (The Jerusalem Pilgrims).
The name Kajsa experienced a slow start with only two years seeing more than five births each between 1970 and 1984. However, it gained popularity in the late 80s to early 90s, consistently ranking among the top names for girls during this period. The peak years were 1990-2005, with an average of 13 births per year. After 2006, Kajsa's popularity fluctuated but remained steady, with a slight dip in recent years (2012-2021). Overall, the name Kajsa has been given to 392 newborn girls since 1970.