The museum building at the Sibelius Museum is one of the most original modernist creations of 1960s Finland. The simple and austere, but at the same time exciting and unique, architecture draws enthusiasts from all around the world. The museum building was inaugurated in 1968 and was designed by architect Woldemar Baeckman, who has also designed other buildings for the Åbo Akademi University. The museum building is included in the Docomomo register selection of modern Finnish architectural masterpieces.

The low museum building differs from the surrounding academic buildings, all of which were erected in the 19th century. The museum building has two floors, one located below ground level. Baeckman planned the Sibelius Museum as a low, rectangular building to enable it to melt into its surroundings among the Empire style buildings of Piispankatu. How well the museum melts into the background is subject to debate. However, for more than sixty years, the museum has hosted a wide range of concerts and exhibitions, enriching the arts scene in Turku.

The museum is built around the concert hall, also known as the Sibelius Hall. Next to the concert hall is the square-shaped atrium, which is surrounded by other museum facilities. The original museum furnishings, such as fixtures and chairs, were designed by interior decorator Carin Bryggman. Since then additions have been made to the design.