Intercalation may refer to:

• Intercalation (chemistry), insertion of a molecule (or ion) into layered solids such as graphite

• Intercalation (timekeeping), insertion of a leap day, week or month into some calendar years to make the calendar follow the seasons

• Intercalation (university administration), period when a student is officially given time off from studying for an academic degree

• Intercalation (geology), a special form of interbedding, where two distinct depositional environments in close spatial proximity migrate back and forth across the border zone

• Intercalary chapter, a chapter in a novel that does not further the plot. See also frame story (sometimes called intercalation).

In biology:

• Intercalary segment, an appendage-less segment in the segmental composition of the heads of insects and Myriapoda

• Intercalation (biochemistry), process discovered by Leonard Lerman by which certain drugs and mutagens insert themselves between base pairs of DNA

• Intercalated cells of the amygdala

• Intercalated cells of the collecting duct

• Intercalated disc of cardiac muscle

• Intercalated duct of exocrine glands