How they are assembled is the primary difference, plus where they originate from. They both contain the same components of meringue, cream and fruit. However, Pavlova stems from Australia and Eton Mess comes from England. With Pavlova, the meringue is kept as a whole and topped with whipped cream, then fruit- checkout my Black Forest Pavlova to get the idea. The meringue in Eton Mess is broken into pieces and layered in individual glasses with the cream and fruit.