Absolutely! A nice advantage of Retract-A-Gate Safety Gate is that it can be installed on a diagonal & work at pretty much ANY ANGLE, opening up numerous mounting options. This is just one of the many great retractable baby gate features which few if any other baby safety gates on the market have.
You can also diagonally attach Retract-A-Gate Safety Gate to a wall farther away from the top of the stairs in order to help keep it back the recommended 6 inches.
For the best security with an angled installation, the openings of the brackets should face away from the Retract-A-Gate.