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

He was known for roles in the Thor film trilogy and the Divergent series, as well several UK TV shows like Band of Gold, Peak Practice and Murphy's Law.

From BBC • May 22, 2023

“I don’t want to reference Murphy’s Law but it has been that way. You have to keep moving on. It’s a long season,” Roberts said.

From Seattle Times • Jun. 18, 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