Affective resonance is an affective dynamic of reciprocal modulation between interactants. Resonance arises through a complex interplay between the capacities to affect and be affected of multiple things and individuals, wherein active and receptive affects are inextricably entangled. “Affective resonance” is thus based on a fundamental reciprocity with regard to the causality of affect, while in the case of the resulting forms and contours, resonance dynamics may be complementary, or even asymmetric, which distinguishes resonance from imitation and synchronization. The concept is presented in the context of a relational and dynamic understanding of affect based on the work of Spinoza and Deleuze.