Pull someone's leg Informal

To joke with someone or tease them playfully, often by telling them something untrue just to get a reaction.

It’s affectionate rather than malicious — used to reassure someone after a joke, as in “relax, I’m just pulling your leg.”

One popular explanation claims the phrase began literally, with Victorian-era London street thieves using a cane or leg-trip to knock a victim off balance before robbing them, the theory being that “pulling someone’s leg” first meant physically tripping them up. This makes a memorable story, but it should be treated with caution: no solid contemporary nineteenth-century documentation supports this specific criminal practice being the source, and the earliest clear print citations of the phrase in its modern joking sense only appear toward the end of the nineteenth century, without any accompanying evidence tying it to street robbery. Many etymologists now treat the connection as an appealing but unproven folk explanation rather than an established fact, and the true origin is generally considered uncertain — possibly linked more loosely to the general image of playfully unbalancing someone, literally or figuratively, rather than any one criminal method.

Relax, I’m just pulling your leg — you don’t actually have to work this weekend.

He told her the office was closed tomorrow, just pulling her leg.

Are you pulling my leg, or is the meeting really cancelled?

A: You won the lottery?! B: No, I’m just pulling your leg.