NBA Star Leandro Barbosa -- Gift-filled Holiday Party in Boston Projects

Boston Celtics star Leandro Barbosa doesn't need a red suit and a beard to play Santa -- in fact, the guard handed out piles of gifts to underprivileged children in Boston yesterday ... wearing nothing but normal street clothes.

A rep for Barbosa tells TMZ, he threw a giant holiday party at the Lenox Housing Development for roughly 80 children -- between the ages of 6 and 16 -- just because he felt like giving back to the community.

Along with a huge array of gifts -- one for each kid -- Barbosa brought 30 delicious PIZZAS.