"Variant of Matteo"
The name Mattheo is commonly a male name from the "Italian" origin.
Mattheo is a spelling variant of Matteo, the Italian form of Matthew. The added h matches the English spelling of Matthew rather than the Italian Matteo, which has a single t and no h. The spelling Mattheo does not appear in United States birth records until 2009.
Matteo means "Gift of God.".
The pronunciation of Mattheo is muh-THEE-oh.