Mattheo is a spelling variant of Matteo and Mateo, the Italian and Spanish forms of Matthew, which comes from the Hebrew Mattityahu and means "gift of God". The double t with h mixes the Italian spelling with the familiar English Matthew. Mattheo was too rare to be recorded in 2000, but it has risen with the broader popularity of Mateo, from number 6940 in 2015 to number 2274 in 2025, its best rank so far.