An eruptive variable is a variable star characterised by sudden extreme increases in luminosity.

There are many different types of eruptive variables, with an enormous range of increases in luminosity and recurrence timescales. Examples include flare stars, which are very faint stars on the main sequence; novae and dwarf novae , which are caused by evolved stars in binary systems; and supernovae, which are the violent and spectacularly luminous end for several classes of star.