Various interspinous process spacing devices and associated methods are provided for treating spinal disease. In one embodiment, an interspinous process spacing device includes a first attachment side and a second attachment side, each attachment side including one or more slots formed therein and positioned proximate one end for receiving fasteners extending inwardly from a second interspinous process spacing device. The device further includes a spacer tray extending from the first attachment side and slideably insertable through a spacer tray slot formed in the second attachment side, wherein the spacer tray is adapted to retain adjacent spinous processes in a spaced apart orientation, and wherein at least a portion of the spacer tray has a longitudinally arcuate shape adapted to facilitate angled insertion of the spacer tray through the spacer tray slot. The device further includes securing means for securing the second attachment side relative to the first attachment side.