Etymologically, gringo comes from griego ("Greek"), since Greek was the proverbial example of not understandable language (as in Shakespeare's "That's Greek to me"). It was then applied to speakers of foreign languages, especially English language. Later it was extended to white-skinned people even if Spanish-speaking, and can sometimes even mean just blonde.

A recurring folk etymology explanation for the derivation of the word states that it originated during the Mexican-American War of 1847. A popular song of the day was "Green Grow the Rushes". Mexicans heard the invading US troops singing "Green grow..." and contracted this into gringo.

Most English language speakers have met the word in Western films.

Compare with Yankee.