Timo Jussi Penttilä (16 March 1931 – 25 February 2011) was one of Finland's most important modernist architects and was for over 15 years a professor at the Academy of Fine Arts Vienna in Austria.

His breakthrough work was Sampola House, the Tampere Adult Education Centre, which Penttilä designed together with Kari Virta in 1958 and which was completed in 1960.

The following year, at the age of 30, Penttilä won the architecture competition for the design of the Helsinki City Theatre, a work which when completed in 1967 received much critical acclaim.

Local grass-roots opposition brought an end to the scheme which had been commissioned by the industrial company Tampella to redevelop an area where their factory then presently stood.

Excerpts from his notes, written in English, have been in published in Roger Connah's book "The School of Exile – Timo Penttilä for and against architecture theory" (2015).