The most likely hypothesis is that they evolved separately. The Ancient Romans already had a a dish similar to the traditional lasagne one called lasana or lasanum described in the book De re coquinaria by Marcus Gavius Apicius, but the word could have a more ancient origin. The first theory is that lasagne comes from Greek λάγανον (laganon), a flat sheet of pasta dough cut into strips. The word λαγάνα (lagana) is still used in Greek to mean a flat thin type of unleavened bread baked for the Clean Monday holiday.

Another theory is that the word lasagne comes from the Greek λάσανα (lasana) or λάσανον (lasanon) meaning "trivet or stand for a pot", "chamber pot". The Romans borrowed the word as "lasanum", meaning "cooking pot" in Latin. Also, the ancient Greek physician Galen mentions a compound of flour and water called itrium, which, in different versions, was also common in late antiquity Palestine.

The story that pasta and asian/chinese noodles were somehow connected was invented in the US in the early 20th century, as an effort to introduce pasta in the American diet.