Fifteen (a.k.a. Hillside) follows the lives of High School students and deals with a variety of issues including dating, alcohol abuse, and friends. Its Nickelodeon's first and only teenage soap opera.
- Chris William Martin (Dylan Blackwell) and Ryan Reynolds (Billy Simpson) are the only actors to appear in both the first and last episodes of the series.
- Chris William Martin (Dylan Blackwell), Todd Talbot (Matt Walker), Laura Harris (Ashley Frasier) and Ryan Reynolds (Billy Simpson) are the only actors to remain with the series throughout its entire run.
- No adults appear on the series.
- Ryan Reynolds (Billy Simpson) is the only actor to appear in all 65 episodes of the series.
- Laura Harris (Ashley Fraiser) appeared in season 2 using her middle name, Elizabeth as a first name and appeared in season 3 using her first name, Laura and her middle initial, E. and appeared in seasons, 1 and 4 using only her first name, Laura.