A horizontally expandable bed rail having a guard rail frame that confronts a first side of a bed to prevent a child from falling out of the bed. The guard rail frame includes a pair of vertical support members interconnected by upper, lower and intermediate horizontal support members that slide horizontally in and out such that the vertical support members have an extended position where the vertical support members are spaced apart by a first distance and a drawn in position where the vertical support members are spaced apart by a second distance that is less than the first distance.