Oikawa has dark brown hair that is swept outwards and eyes of the corresponding color. Many people find him attractive, to the point where several girls follow him around. Oikawa frequently smiles or grins, although Iwaizumi notes that these expressions are rarely genuine. He tends to make victory signs or large waving gestures, which are often accompanied by broad smiles or a wink. Another trademark expression of his is sticking out his tongue while smiling and winking.