The relationship between the original parties to a covenant or equitable servitude. To establish horizontal privity, the promisor and promisee must share an interest in the real property independent of the covenant or equitable servitude at the time the promise is made, such as in connection with the conveyance of an interest in the property. This requirement is satisfied when the promisor and promisee are:

Conversely, if two adjacent landowners simply agree to be bound by a promise for their mutual benefit, no horizontal privity exists and subsequent owners of the land are not bound.

Horizontal privity may determine if a real covenant runs with the land.