Millie Adebayo is a Year 9 student at Waterloo Road High School.
Millie is a friend of Caz Williams and Shola Aku. When Caz is complaining to Kim Campbell about the new uniform not being gender neutral, Millie accompanies her to Kim’s office. She later holds Caz's crutches in the playground on one occasion while she is using her wheelchair.
In Series 11 Episode 5, Izzy Charles borrows Millie's phone to call her father after overhearing Coral Walker confessing the truth about causing her mother's death.
In Series 12, Millie is among the pupils who sing "Before you Go" by Lewis Capaldi after Danny Lewis's death.
Millie only appears briefly twice in Series 13, once in Series 13 Episode 7 in Amy Spratt's class when Caz is talking about studying environmental law, and again at the end of Series 13 Episode 8 when the students enjoy free pizza to celebrate the end of term.
In Series 14, Millie is seen helping the other sixth-formers to sneak musical instruments out of the school to perform the Battle of the Bands elsewhere in support of Val Chambers after they believe that she has been sacked. She performs at the event as a member of Preston and Noel's band.
Millie is later seen at Preston's 'surprise' 18th birthday party at the very end of the series.