Tire sensor packaging capable of being installed on a standard snap-in tire valve stem is provided. The sensor package includes an attachment member capable of being disposed in the flexible bore of a snap-in tire valve stem, and of securely engaging with the inner wall of the flexible bore. The attachment member can be an integral part of the sensor package, or it can be a separate part that acts as an expansion device (e.g., an expansion nut) when engaged with the sensor package. Preferably, the attachment member includes features, such as barbs, to provide more secure engagement with the tire valve stem. Packages according to embodiments of the invention include a package passage (e.g., a channel or a bore) to permit the flow of air past the sensor, so that the tire can be inflated or deflated. Sensors can be attached to the tire valve stem before or after the tire valve stem is installed in the wheel.