One Good Turn Deserves Another: Origin and Meaning

If you do something good for me, I will do you a favour in the same way. It is usually used in a positive way, to support each other in small acts of kindness, but can be used to talk about corruption, and the “turns” could be criminal actions that will help another criminal.

This idiom has been in English for a long time- since at least the 1650s, though probably in spoken English for longer. It is thought of as a translation of the older Latin Quid pro quo- something for something else, which is sometimes used in more formal English with the same meaning as our idiom here.

– Why did you give her that extra help with her writing?
– Well, she helped me with my maths, and one good turn deserves another!
– Come on, help us out here. We didn’t tell the police about your stealing, and one good turn deserves another.