The present disclosure is directed to cable tensioning systems for use in railings and barriers. The cable tensioning assembly can be used in railings and barriers that utilize vertical or horizontal cables. The present assembly includes a tension bar which runs along the rails of the railing system and has a plurality of equidistant pairs of apertures. Each pair of apertures secures an end of a cable and accepts a tension adjuster. The tension adjuster of one embodiment threadably engages with the rail to pull the tension bar close to the rail and apply tension to the cable. The tension adjuster of another embodiment threadably engages with the tension bar to push the tension bar closer to the rail and apply tension to the cable.