St Mungo's Academy Annexe, 11 Barony Street, Glasgow

St Mungo's Academy Annexe, built in 1895-1898, was designed by Charles Rennie Mackintosh of John Honeyman and Keppie. It is a compact, three-storey and basement school building constructed from red Ballochmyle freestone, with squared and snecked ashlar dressings. The design incorporates bracketted cill and lintel courses, often in stylized forms, linking windows and extending to single windows. The eaves elevation features a variety of cornice forms.

The north elevation is a seven-bay, symmetrical block, with flanking bays set back and gabled. The centre bay has a blocked basement doorway and a bipartite window above. Outer bays on each side have windows in each bay. A quasi-balcony runs across the first-floor groups, while the second-floor groups are linked at cill and cornice levels, with the cornice raised in keystoned, shaped pediments at the centre. The return elevations are simpler, featuring two bays. Entrances are recessed within gables, forming a mirrored pair, with each door set within an advanced panel, featuring a keystone and ogee carving to the lintel above, and distinctive flanking ornament. Double doors incorporate tear drop panels. A bracketted string course above includes a quasi-balcony and two narrow windows illuminating the stairwell, with a further small window at the third-floor level and a bracketted cill.

The south elevation has nine bays with grouped windows, and an advanced square stack with bracketted, overhanging coping towards the east. A doorway is centrally positioned in the centre group of bays, featuring a bracketted porch and a square fanlight above. Fenestration is generally plain, with some linking cill and lintel details.

The east and west elevations are similarly detailed, with a stairwell defined by two narrow windows and mullioned and transomed broad, round arched windows above, beneath deeply swept eaves. Narrow stair windows are present to the right and left, respectively. A subtle variety of windows is applied to the rest of the elevation. Sash and case windows feature small-pane upper sashes and two-pane lower sashes, while stairwell windows utilize square lead-pane glazing. The roof is covered in grey slates, with coped stacks. Two ogee ventilators feature decorative knot and finial detailing with leaded bases (previously with a balustrade).

The interior is largely symmetrical, with a galleried light-well at the centre and stairs to the east and west. Walls are tiled to wainscot level with green tiles at the top. Archways lead to corridors, and doors have small-pane upper panels. Glasgow Style screens were removed in 1988 (planned for return), alongside mannered roof trusses and Glasgow Style stair newels. The building was undergoing repair in 1988.

Retaining walls and gates enclose entrance courtyards. The walls are of ashlar construction, with a balustrade on the east side and a partial balustrade on the west. Two sets of decorative wrought iron gates are present.