Abstract: A sliding truck window bar lock includes a pair of bars, each bar being hingedly mounted atop a vertically oriented post and collar asembly and adapted for mounting to the rear wall of a passenger compartment in a pick-up truck such that an operator may move the bars into a locking orientation intermediate the edge of a sliding glass window and the window frame. Each bar may consist of a pair of telescoping tubes, each tube having a plurality of holes such that they may be telescoped in and out to align the holes and adjust the effective length thereof.