The Sir Leonard Tilley Building and Annex (French: Édifice Sir-Leonard-Tilley), is a Government of Canada office building property consisting of two buildings and operated by the Public Works and Government Services Canada and located at 719 Heron Road in Ottawa, Ontario, Canada.

[1] It was designed by architect Jean-Serge Le Fort.

Until 2015, the building housed the headquarters of the Communications Security Establishment (CSE).

This building was named in honour of Samuel Leonard Tilley, federal Finance Minister in 1873–1878.

Public Works Canada is preparing the buildings to allow other government departments to take their place.