'jalopy' originates from early 20th-century American English slang, probably ultimately from the Spanish place name 'Xalapa' (also spelled 'Jalapa'), a city in Mexico; the exact origin is uncertain.

'jalopy' appeared in U.S. slang in the 1910s–1920s (variants like 'jaloppy' are attested) and, perhaps influenced by the place name 'Xalapa/Jalapa' or other folk formations, stabilized as the modern English word 'jalopy'.

Initially it may have referred to cheap, often imported or secondhand cars (sometimes associated with cars bought near Xalapa), but it has come to mean any old, rundown or unreliable automobile.