Thirteen-year-old Kayla endures the tidal wave of contemporary suburban adolescence as she makes her way through the last week of middle school — the end of her thus far disastrous eighth grade year — before she begins high school.
| Actor | Role |
|---|---|
 Elsie FisherKayla Day | Kayla Day |
 Josh HamiltonMark Day | Mark Day |
 Emily RobinsonOlivia | Olivia |
 Jake RyanGabe | Gabe |
 Daniel ZolghadriRiley | Riley |
 Fred HechingerTrevor | Trevor |
 Imani LewisAniyah | Aniyah |
 Luke PraelAiden | Aiden |
 Catherine OliviereKennedy | Kennedy |
| NNora MullinsSteph | Steph |
 Gerald JonesTyler | Tyler |
 Missy YagerMrs. Graves | Mrs. Graves |
 Shacha TemirovMason | Mason |
 Greg CroweMr. McDaniel | Mr. McDaniel |
 Thomas J O'ReillyEdmund | Edmund |
 Frank DealOfficer Todd | Officer Todd |
 J. Tucker SmithMr. Graves | Mr. Graves |
 Tiffany GrossfeldBabs | Babs |
| TTrinity Goscinsky-LynchDylan | Dylan |
 Natalie CarterMrs. Roach | Mrs. Roach |
 Kevin R. FreeMr. Denkert | Mr. Denkert |
| KKeith Maurice DavisHigh School Boy | High School Boy |
 Deborah UngerMrs. Nolan | Mrs. Nolan |
| WWilliam Alexander WunschBrave Boy | Brave Boy |
 Marguerite StimpsonPuberty Video Instructor | Puberty Video Instructor |
| TTristan WheelerAndrew Fields | Andrew Fields |
| KKylie SeamanKristen S. | Kristen S. |
| DDylan VonderhorstDawn Ringlehein | Dawn Ringlehein |
| LLuke MulliganJed Goodwin | Jed Goodwin |
| LLouisa Rose GuarasciJackie S. | Jackie S. |