The Western Dry Dock and Shipbuilding Company was a shipyard that operated at Port Arthur, Ontario, now part of Thunder Bay, on Lake Superior from 1911 to 1993. The shipyard was established in 1909 and renamed in 1916 as the Port Arthur Shipbuilding Company. The yard closed in 1993. It reopened as a repair yard Lakehead Marine and Industrial, however that venture failed in 2014. As of 2016, the shipyard was purchased by Heddle Marine. It is operated by Heddle Marine in partnership with Fabmar Metals Inc, of Thunder Bay. The venture focuses on ship repair services and winter layup options.

Port Arthur was a city in Northern Ontario, Canada, located on Lake Superior. In January 1970, it amalgamated with Fort William and the townships of Neebing and McIntyre to form the city of Thunder Bay.