Ulla-Maj Wideroos, born 22 October 1951 in Jakobstad, Finland, is a Finnish politician in the Swedish People's Party (SFP), who was the second Minister of Finance in the Vanhanen government I between 24 June 2003 and 19 April 2007. Wideroos, who holds a master's degree from 1971, began her political career in Swedish Youth, where she was ombudsman from 1973-1974. She became municipal director of Oravais in 1986. In 1995, she was elected to the parliament and left the position of municipal director. On April 17, 2003, she took over as the second Minister of Finance in the Jäätteenmäki government, a post she was allowed to keep when Anneli Jäätteenmäki resigned and Matti Vanhanen reshuffled the government.

Wideroos lives in Närpes. She is married and has an adult son.