It is a patronymic surname, meaning it is derived from a given name. In this case, it is a variation of the name Paolo (Paul in English). The "Di" prefix is a common Italian preposition meaning "of" or "from", so DiPaola literally translates to "of Paul".
The surname is primarily found in Southern Italy, particularly in the regions of Sicily and Calabria.
It is a relatively common surname in Italy and has also been adopted by Italian-Americans in the United States.