Louis-Phillip Edmonston (26 May 1944 – 2 December 2022) was a Canadian consumer advocate, writer, journalist, and politician. Along with Andrew Scheer, he was one of the few politicians with dual American and Canadian citizenship to be elected to the Parliament of Canada.

Edmonston was best known for his series of annual Lemon-Aid car guides. He lived in Panama at the end of his life.

Born on 26 May 1944, in Washington, D.C., Edmonston served as a United States Army infantry medic in Panama from 1961 to 1964, where he witnessed the so-called flag riots, and graduated from the Canal Zone College. He subsequently immigrated to Montreal, where he became known as a journalist and consumer advocate.

In journalism, Edmonston worked as a television reporter, a syndicated newspaper columnist, and a host of his own open-line show.

In 1968, he founded the Automobile Protection Association (APA), which uncovered and disseminated information about automobile defects and successfully pressured the auto industry for several recalls. Edmonston was president of the APA until 1987. In that role, he worked on thousands of consumer claims against automobile manufacturers and won million-dollar settlements and hundreds of lawsuits for consumers.

His work with the association led to the Lemon-Aid series of car manuals, issued annually since the 1970s.

Edmonston served as a pro bono witness on automobile defects and safety before numerous courts and government committees. In 1982, he testified on inadequate automobile quality and rust protection before the United States Senate Subcommittee on Technology and successfully pressured Ford to become the first automaker to provide a corrosion compensation warranty. In Canada Edmonston's Rusty Ford Owners Group sued Ford and eventually won an agreement with Ford and other automakers as well as the federal government to guarantee cars for five years against perforation.

Edmonston was the author of over 100 best-selling books on consumer rights and the automobile industry.