Centre Block, Parliament building at Parliament Hill in Ottawa, Canada.

Centre Block is the main building of Canada's Parliament on Parliament Hill in Ottawa, a symmetrical Gothic Revival structure 144 m long and 75 m deep, six storeys high. Its walls are faced with over 50,000 blocks of more than 24 types of stone, mainly Nepean sandstone, around 550 windows, and its copper-covered roof has dormer windows. Inside, Confederation Hall is an octagonal chamber with limestone columns, a fan-vaulted ceiling and a central column carved with Neptune.

The first Centre Block burned in 1916, leaving only the Library of Parliament at the rear. Construction of its replacement by architects John A. Pearson and Jean-Omer Marchand began immediately, and the new building was completed in 1927. Interior sculpting continued into the 1970s, and in 2018 members of Parliament moved out for renovations expected to last until 2031.

The name comes from its position between the East and West Blocks on Parliament Hill. In Confederation Hall, the gables carry the coats of arms of the provinces and territories framed by local plants: thistles for Nova Scotia, grapevines and apples for Saskatchewan, sunflowers and wheat for Alberta. The gable ramparts show symbols of Canada's fauna.

The building remains under full renovation until 2030, with parliamentary sessions currently held in other government buildings across downtown Ottawa. The Peace Tower stays partially accessible to visitors during construction work, though most interior spaces are closed.

The renovation project involves replacing 1,600 windows and restoring 250 stained glass panels throughout the building. Some original sandstone will be replaced during the work with new blocks from the same historic quarries.