Oshawa is a provincial electoral district in Ontario, Canada, that has been represented in the Legislative Assembly of Ontario since 1955.
In 2015 the provincial districts were updated, and Oshawa gained parts of the city which were previously part of the electoral district of Whitby-Oshawa. The 2018 provincial election was the first in which the new borders were used. The new borders include most of the actual city of Oshawa, although it excludes the mostly rural areas from Wards 4, 6, and 7 north of Taunton Road. These northern parts are part of the Durham electoral district.
Previously the district of Oshawa consisted of the southern and eastern parts of the City of Oshawa south and east of a line drawn from west to east along King Street West, north along Oshawa Creek, east along Rossland Road West, north along Simcoe Street North and east along Winchester Road East. The riding includes the communities of Kedron and Taunton and the eastern part of North Oshawa. In 1999, provincial ridings were defined to have the same borders as federal ridings. The federal district was also re-mapped to include the north-western sections.