Voiced by: Satomi Satō (Japanese), Cassandra Lee (English)
Ritsu (or Rit-chan, as nicknamed by Yui) is the self-proclaimed president of the light music club and plays a yellow Rick Marotta Signature Yamaha Hipgig drum kit with an add-on floor tom (in the opening credits only) combined with a cymbal set from Avedis Zildjian, though is shown playing a white Yamaha Absolute Series drumkit in the anime's closing credits. She has an ambiguous yet upbeat personality, much like Yui, but often has trouble remembering important club activities and announcements and gets constantly rebuked by Mio and Nodoka for forgetting to send in important forms concerning the club. Ritsu is cheerful, often likes making jokes and is sarcastic most of the time. She is skilled at brainstorming ideas that earn money for the club. Ritsu has shoulder-length, brown hair, with her bangs pulled back with a yellow hairband, and gold-colored eyes. She wears her school jacket open. She says she chose to play the drums because they are "cool", but she then admits that she has trouble playing instruments which involve intricate finger movements, such as the bass, guitar and keyboard.
She is a childhood friend of Mio and will often have the opportunity to tease her whenever she is cowering from something. She is also known to become easily jealous of Mio's other high school friends, even going as far as spying on her when on outings with them. Ritsu is always on the go and will stop at nothing for the success of the light music club. Despite her rough mannerisms and speech, she gets cast as Juliet by the majority of her classmates in their class play rendition of Romeo and Juliet and, in the end, manages to act like a proper girl. In the anime, she states her favorite drummer is Keith Moon of The Who. She is skilled at cooking. She has a younger brother named Satoshi (聡, Voiced by: Mika Itō).