In this paper we develop a formal framework for the systematic study of when a mathematical property (P) that holds for one structure (A) can be transferred to another structure (B). We introduce the concept of a property transfer operator and establish basic conditions under which the implication A ->_P B is valid. By examining classical results from algebra, topology, and analysis through the lens of transfer theory we reveal a unifying theme behind many seemingly disparate generalization theorems. We also discuss structural prerequisites, such as homomorphisms, embeddings, and categorical limits, that facilitate property transfer. The theory presented here provides a new language to express and prove transfer results and suggests avenues for future research in areas where cross-domain generalizations are sought.