A revolutionary wave or revolutionary decade is one series of revolutions occurring in various locations within a similar time-span. In many cases, past revolutions and revolutionary waves have inspired current ones, or an initial revolution has inspired other concurrent "affiliate revolutions" with similar aims. The causes of revolutionary waves have become the subjects of study by historians and political philosophers, including Robert Roswell Palmer, Crane Brinton, Hannah Arendt, Eric Hoffer, and Jacques Godechot.

In political science, a revolution is a rapid, fundamental transformation of a society's state, class, ethnic or religious structures. A revolution involves the attempted change in political regimes, substantial mass mobilization, and efforts to force change through non-institutionalized means.