Ling Su Wong is a student at Albert Einstein High School and a friend of Mia's. She is made Treasurer of the student government, even though she told Mia she was no good with money. She has illegible artist handwriting, being a very gifted artist. Her screen name is painturgurl.
Ling Su was part of the chorus in the musical Braid in the seventh book. She sent a message to Mia saying that if she got a mistress part, it would be typecasting, as that is what she claims Asian Americans are usually made to play.
In the final book, Ling Su and Perin attend the prom together and Meg Cabot has confirmed that they are a couple. In Mia's list of people she loves in the seventh book, Ling Su is ninth, along with Shameeka and Perin, below Tina Hakim Baba and above Mia's stepfather Mr Gianini.