Murphy's Law

American  

noun

1. the facetious proposition that if something can go wrong, it will.

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Murphy's law British  

noun

1. informal another term for Sod's law

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Murphy's Law Cultural  

1. A rule that states, “If something can go wrong, it will.” An addition to this law reads, “and usually at the worst time.” The identity of “Murphy” is unknown, but the saying was first used during the 1940s and may have originated with members of the armed forces in World War II.

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Murphy's law Idioms  

1. If anything can go wrong, it will, as in We may think we've covered all the details for the benefit, but remember Murphy's law. The identity of Murphy, if ever a real person, is unknown. Some think it alludes to (but was not invented by) a feckless Irishman named Murphy. [c. 1940]

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Etymology

Origin of Murphy's Law

An Americanism dating to 1950–55; named after Edward A. Murphy, Jr., (1918–90), an American aerospace engineer who worked on safety systems

Example Sentences

Byrne stars as Linda, a woman looking Murphy’s Law dead in the eye and screaming in its face.

From Salon • Feb. 6, 2025

In 1982 the top 20 single Murphy's Law became the only chart hit for which Canadian chart act?

From BBC • Dec. 23, 2022

Dr. Robinson remembered thinking of Murphy’s Law and joking, “I know exactly where it’s going to hit.”

From New York Times • Jun. 27, 2022

“They say when you’re shooting a movie, Murphy’s Law happens,” said Samuel.

From Los Angeles Times • Nov. 3, 2021

And of course, Murphy’s Law, the year my mom started buying my clothes too big was the year that I stopped growing.

From "Born a Crime: Stories from a South African Childhood" by Trevor Noah