Alexandra Building, Heritage building in Queensland, Australia.

The Alexandra Building is a two-storeyed masonry building at 451–455 Ruthven Street, Toowoomba, designed by Harry Marks and built in 1902 by James Renwick. Its Ruthven Street frontage has an upper-floor verandah with a cast-iron balustrade over the pavement, and a decorative three-gabled face-brick parapet bearing "Alexandra Hall" in relief on the middle gable.

Built in 1902 for confectioner Thomas Kelsall Lamb, the Alexandra Building was designed by Toowoomba architect Harry Marks and erected by builder James Renwick. Its upper floor held a hire hall for balls, banquets and concerts, while two shops occupied the ground floor; Marks added a rear extension in 1905. It joined the Queensland Heritage Register on 16 October 2008.

The building is named after Queen Alexandra, wife of Edward VII, whose coronation in August 1902 coincided with the opening of TK Lamb's new premises. The middle gable carries the words "Alexandra Hall" in relief, a name tied to the hire hall upstairs where balls, banquets, wedding receptions and concerts were held.

The building stands at 451–455 Ruthven Street, between Russell and Margaret Streets, in Toowoomba's central business district. The two-storey frontage, upper-floor verandah with cast-iron balustrade and three-gabled face-brick parapet are seen from the Ruthven Street footpath; the 1905 extension is at the rear.

The three-gabled face-brick parapet carries the words "Alexandra Hall" in relief on the middle gable, a detail easily missed at street level. The name honours Queen Alexandra, wife of Edward VII, whose coronation in August 1902 coincided with the building's opening.