Olav Selvaag (17 December 1912 – 14 January 2002) was a Norwegian engineer and residential contractor, known for his innovative approach to designing and building affordable housing during the later half of the twentieth century.

His father, Ole Walaas Selvaag (1870–1930), was a medical doctor who rose to prominence as a public health official at the district and county level; and was also a member of parliament for the Liberal Party.

Selvaag brought much-needed structural engineering expertise to the firm, and Ringnes seemed to appreciate this, increasing his salary after only 10 days and delegating more and more of the leadership responsibilities to him.

[5] During the occupation of Norway by Nazi Germany during World War II, Selvaag and Ringnes were among the very few firms of their time to immediately take a principled stand against performing any construction project for the occupying powers.

[1] Selvaag gained his reputation as an innovator in the austere post-war years, when he wrote an open letter (with drawings) to the Norwegian parliament (with copies to twelve leading newspapers) severely criticizing residential regulations and codes for their inefficiency, and claiming that three times as many residences could be built with the same amount of materials and effort.

He was asked to serve as minister of industry in the short-lived John Lyng cabinet, but turned the invitation down, citing his wish to remain independent.

[1][10] Selvaag's contribution to the housing scarcity in Norway following World War II, and subsequent years, created entire urban neighborhoods, especially in the Greater Oslo Region.