We introduce a support variety theory for the category algebras of transporter categories. It extends Carlson鈥檚 support variety theory on group cohomology rings to equivariant cohomology rings. In the mean time it provides a class of (usually non selfinjective) algebras to which Snashall-Solberg鈥檚 (Hochschild) support variety theory applies. Various properties will be developed. Particularly we establish a Quillen stratification for modules.