Dyadic may refer to:

• Adicity / arity of a mathematical relation or function (dyadic relations are usually called binary relations)
• Dyad (sociology) - as an adjective, describes the interaction between a pair of individuals. A dyad can be linked via general communication, romantic interest, family relation, interests, work, partners in crime, and so on.
• Dyadic counterpoint, the voice-against-voice conception of polyphony
• Dyadic distribution, a type of probability distribution
• Dyadic fraction, a mathematical group related to dyadic rationals
• Dyadic solenoid, a kind of dyadic fraction
• Dyadic data: data composed of two sets of objects A and B, in such a way that observations are observations of couples (a, b), with ${\displaystyle a\in A}$ and ${\displaystyle b\in B}$.