Pat Lowther (July 29, 1935-September 24, 1975) was a Canadian poet.

Born Patricia Louise Tinmuth, she grew up in North Vancouver, British Columbia. Her first published poem appeared in the Vancouver Sun when she was ten years old.

In 1963, she married Roy Lowther. In 1968, her first collection, This Difficult Flowring, was published by Very Stone House, a small poetry press operated by Seymour Mayne and Patrick Lane. Lowther's precision with image and language was popular with critics.

In 1972, The Age of the Bird was published by Blackfish Press. This long poem expressed Lowther's concerns for South American revolutionary politics, and included a poem for Pablo Neruda, an important political and inspirational figure for Lowther. In 1974, Milk Stone was published by Borealis Press, and became Lowther's breakthrough into the mainstream of Canadian literature. In 1975, A Stone Diary was accepted for publication by Oxford University Press.

However, in late September of that year, Lowther disappeared. Her body was discovered three weeks later in Furry Creek, near Squamish, British Columbia. Roy Lowther was convicted of her murder in June 1977. He died in prison in 1985.

A Stone Diary was published by Oxford in 1977. In 1980, a collection of early and unpublished poems entitled Final Instructions was released.

In 1980, the League of Canadian Poets established the Pat Lowther Award, an annual prize to honour a book of poetry by a Canadian woman.

Lowther's tragic death was also the inspiration for Carol Shields' 1987 novel Swann; the title of her A Stone Diary may also have inspired the title of Shields' The Stone Diaries.