There are strong formal similarities between the condition for anomalous Doppler resonance in plasmas ( omega -k/sub ///v/sub ///=- Omega , where omega is the frequency of the perturbing wave field, k/sub ///v/sub /// measures the Doppler shift due to guiding-centre motion, and Omega is the cyclotron frequency) and the condition for inner Lindblad resonance in stellar discs ( Omega b- Omega 0=- kappa /m, where Omega b is the frequency of the perturbing wave field, whose azimuthal harmonic number is m, Omega 0 is the natural frequency of equilibrium guiding-centre circulation, and kappa is the epicyclic frequency). It is shown that this similarity reflects a close underlying correspondence between the two forms of resonance.