House's best-known catchphrase is “Everybody lies.”
The phrase expresses Gregory House's belief that patients, colleagues, and other witnesses often hide information or present events inaccurately. In the show's diagnostic logic, a misleading history can lead doctors toward the wrong diagnosis, so House treats every statement as evidence that must be tested rather than accepted automatically.
“Everybody lies” is not simply a medical rule. It also reflects House's cynical view of human behavior and his difficulty trusting people. The phrase recurs throughout the series and became closely associated with the character in popular culture.
The wording appears in related forms across episodes, including the title of the first-season episode “Everybody Lies.” It should not be confused with “Everybody Dies,” the title of the series finale. The two phrases are deliberately similar, but they refer to different episodes and ideas: one is House's diagnostic maxim, while the other names the final episode and its theme of mortality.