North Quay retaining wall, Heritage-listed retaining wall in Brisbane City, Queensland, Australia

The William Street retaining wall is a rough-coursed porphyry (Brisbane Tuff) embankment with a parapet, sandstone coping and decorative cast-iron railing, running about 70 metres along William Street between Queen and Elizabeth Streets. It reaches a maximum height of 4.5 metres on the Queens Wharf Road frontage. A marble pedestal inscribed "WM Galloway Mayor 1889" ends the wall at the Victoria Bridge side, carrying a gas lamp stand marked Smith, Faulkner & Co. 1889.

Planned in 1888 to give William Street an aesthetic setting opposite the new Treasury Building, the wall replaced the Victoria Bridge end of an old rubble wall. Contractor EJ O'Connor, who had stabilised the Petrie Bight porphyry wall, built it for £1431, and it was finished by 1889 when Cabinet first met in the Treasury. A 1936 masonry and iron wall opposite marks the ramp to Hayles Wharf; in the early 1970s about 20 metres were demolished for the Elizabeth Street off-ramp.

The wall's Victoria Bridge end is closed by a marble pedestal inscribed "WM Galloway Mayor 1889", a gift to Mayor William McNaughton Galloway from the Mayor of Adelaide, who had visited Brisbane while the wall was being finished. It carries a gas lamp stand marked Smith, Faulkner & Co. 1889, the local firm that also cast the railing.

The wall runs along the William Street footpath between Queen and Elizabeth Streets, opposite the Treasury Building, and is reached on foot from the city centre. The Queens Wharf Road level below holds the interwar stairwell, the men's toilet block marked BCC and the concrete air-raid shelter. The 1944 bus shelter above remains a main stop for buses to Brisbane's southern suburbs.

The wall's marble end post at the Victoria Bridge end is inscribed "WM Galloway Mayor 1889"; it was a gift to Mayor William McNaughton Galloway from the Mayor of Adelaide, who visited Brisbane while the wall was being finished. The gas lamp stand above it bears the words Smith, Faulkner & Co. 1889.