Subaru Hasegawa harbors the ambition to become one of the greatest basketball superstars of all time. However, this dream appears to stall when his school's basketball team suspends activities for a year. Shocked by the news, he decides to step away from basketball entirely. One day, his aunt Mihoshi Takamura invites him to coach the Keishin Academy girls’ basketball team, teaching them how to play the sport, and he reluctantly agrees. He meets sixth-graders Tomoka Minato, Maho Misawa, Airi Kashii, Hinata Hakamada, and Saki Nagatsuki, and begins training them with a single goal: to defeat every strong opponent they face. Ro-Kyu-Bu! follows the efforts of five elementary school girls and their coach as they refine their cute style of playing basketball.