Abstract: A mounting device is disclosed for a portable, expansion-type security gate for children or pets. The expansion gate has a variable width with frictional bumpers on each side that frictionally engage a door jamb or other doorway defining member. The mounting device consists of a socket defining mounting member for each frictional bumper that is secured to the door jamb and is configured to receive and retain the frictional bumper. One type of mounting member is configured to mount on flat surfaces such as door jambs and walls. Another mounting member is constructed to mount on a wrought iron railing. Both types rigidly support the security gate and prevent it from being accidentally dislodged.