Reciprocity theorem

Reciprocity theorem may refer to:
 * Quadratic reciprocity, a theorem about modular arithmetic
 * Cubic reciprocity
 * Quartic reciprocity
 * Artin reciprocity
 * Weil reciprocity for algebraic curves
 * Frobenius reciprocity theorem for group representations
 * Stanley's reciprocity theorem for generating functions
 * Reciprocity (engineering), theorems relating signals and the resulting responses
 * including Reciprocity (electrical networks), a theorem relating voltages and currents in a network
 * Reciprocity (electromagnetism), theorems relating sources and the resulting fields in classical electromagnetism
 * Tellegen's theorem, a theorem about the transfer function of passive networks
 * Reciprocity law for Dedekind sums
 * Betti's theorem in linear elasticity