A gas assisted liquid spray nozzle assembly comprising: a nozzle body defining a mixing zone and a downstream barrel extension zone, said mixing zone communicating with said barrel extension zone, an elongated liquid injector within said nozzle body defining a steam chamber between said nozzle body and liquid injector, the elongated liquid injector extending into the mixing zone along a central axis of the mixing zone, a liquid inlet directing a pressurized liquid into said liquid injector, a steam inlet coupled to a steam or other gas supply directing steam or other pressurized gas into said steam chamber, said liquid injector being a tubular body member and having a liquid inlet extension passageway and a plurality of discharge orifices extending transversely through the liquid injector adjacent a downstream end of said extension passageway arranged in use to direct liquid from said extension passageway into the mixing zone in transverse relation to the central axis of the mixing zone, a spray tip mounted at a downstream end of said barrel zone having a discharge orifice arranged to discharge atomized liquid from said barrel zone in a spray pattern characterized by said steam chamber comprising a plate like steam wall member within said tubular body member, said steam chamber being connected to the mixing and barrel zones (20, 24) by a plurality of steam discharge orifices each being aligned precisely with a respective liquid discharge orifice of the liquid injector for directing steam over the respective liquid discharge orifice for direct shearing and atomization of a discharging liquid stream at the precise location of the liquid discharge orifice. a nozzle body defining a mixing zone and a downstream barrel extension zone, said mixing zone communicating with said barrel extension zone, an elongated liquid injector within said nozzle body defining a steam chamber between said nozzle body and liquid injector, the elongated liquid injector extending into the mixing zone along a central axis of the mixing zone, a liquid inlet directing a pressurized liquid into said liquid injector, a steam inlet coupled to a steam or other gas supply directing steam or other pressurized gas into said steam chamber, said liquid injector being a tubular body member and having a liquid inlet extension passageway and a plurality of discharge orifices extending transversely through the liquid injector adjacent a downstream end of said extension passageway arranged in use to direct liquid from said extension passageway into the mixing zone in transverse relation to the central axis of the mixing zone, a spray tip mounted at a downstream end of said barrel zone having a discharge orifice arranged to discharge atomized liquid from said barrel zone in a spray pattern characterized by said steam chamber comprising a plate like steam wall member within said tubular body member, said steam chamber being connected to the mixing and barrel zones (20, 24) by a plurality of steam discharge orifices each being aligned precisely with a respective liquid discharge orifice of the liquid injector for directing steam over the respective liquid discharge orifice for direct shearing and atomization of a discharging liquid stream at the precise location of the liquid discharge orifice.