Roos is a full member of the Finnish Academy of Sciences from 1995.

In 1948 he became a member of the Finnish Academy.

The Finnish Academy of Science and Letters made him a foreign member in 1992.

He is a member of the Finnish Academy of Sciences.

So stated Aalto in 1955 during the inaugural lecture at the Finnish Academy.

Later, he also became member of the Swedish (1928) and Finnish (1932) Academies.

He became an honorary professor in 1942 and was elected to the Finnish Academy in 1948.

He was a member of the Finnish Academy of Science and Letters.

He is a member of the Finnish Academy of Science and Letters since 2009.

In 1959 he was made a member of the Finnish Academy (one of Finland's highest honors).