Polymorphism, polymorphic, polymorph, polymorphous, or polymorphy may refer to:
- Polymorphism (computer science), the ability in programming to present the same programming interface for differing underlying forms
- Ad hoc polymorphism, applying polymorphic functions to arguments of different types
- Parametric polymorphism, abstracts types, so that multiple can be used with a single implementation
- Subtyping, different classes related by some common superclass can be used in place of that superclass
- Row polymorphism, uses structural subtyping to allow polymorphism over records
- Polymorphic code, self-modifying program code designed to defeat anti-virus programs or reverse engineering
- Polymorph, a shapeshifting being in:
- Polymorph, a magical spell in many fantasy role-playing games that transforms a target into one of many different creatures for a period of time