William Archibald Borthwick AM (20 November 1924 – 31 July 2001) was an Australian politician.

Borthwick was a Liberal Party member of the Victorian Legislative Assembly for the electorates of Scoresby (1960–1967) and Monbulk (1967–1982).

[2] Borthwick was elected to the Victorian Legislative Assembly in a September 1960 by-election for the seat of Scoresby triggered by the death of the sitting MP, Sir George Knox.

[1] Bill Borthwick made a significant contribution to Victoria's environmental policies through the establishment of the Land Conservation Council in 1971 (now Victorian Environmental Assessment Council) which insulated controversial public land management recommendations from political interference.

[4] In the 1987 Queen's Birthday honours, Borthwick was made a Member of the Order of Australia (AM) in recognition of service to the Victorian parliament and to the community.