The current article presents a basic functional-analytic interpretation of metaphor. This work involves an extension of Skinner's (1957) interpretation of metaphor using relational frame theory (RIFT). A basic RIFT interpretation of a particular metaphor is outlined, according to which the metaphor acquires its psychological effects when formal stimulus dimensions are contacted via the derivation of arbitrary stimulus relations. This interpretation sees the metaphor as involving four elements: (a) establishing two separate equivalence relations, (b) deriving an equivalence relation between these relations, (c) discriminating a formal relation via this equivalence-equivalence relation, and (d) a transformation of functions on the basis of the formal relation discriminated in the third element. In the second half of the paper, a number of important issues with regard to the RFT interpretation of metaphor are addressed.