In mathematics, oscillation theory specifies that a solution to an ordinary differential equation is oscillating if it has an infinite number of roots.
Oscillation theory may also refer to:
Oscillation theory, proposed in 1930 by Erich Haarmann, that the Earth’s crust changes because of drag forces
Oscillation theory, land-level rise and subsidence during deglaciation, proposed by N. O. Holst (1899), Ernst Antevs (1921) and Astrid Cleve (1923)