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Season 3 of Andi Mack was announced on February 19, 2018 during a cast interview with Good Morning America. The season premiered on October 8, 2018.
Andi is increasingly confident about expressing herself as she navigates her relationship with Jonah Beck and new territory in her long-standing friendships with Buffy and Cyrus. She continues to work on building a family unit with her parents, Bex and Bowie, who are new to parenting but are doing their best through humor, love and open communication. Andi’s grandparents, Celia and Ham, are still very much in the picture to provide her with additional support.
- Peyton Elizabeth Lee as Andi Mack
- Joshua Rush as Cyrus Goodman
- Sofia Wylie as Buffy Driscoll
- Asher Angel as Jonah Beck
- Trent Garrett as Bowie Quinn
- Lilan Bowden as Bex Mack
- Lauren Tom as Celia Mack
- Emily Skinner as Amber
- Luke Mullen as TJ Kippen
- Darius Marcell as Walker Brodsky
- Oliver Vaquer as Dr. Metcalf
- Stoney Westmoreland as Ham Mack
- Colleen Camp as Cookie Quinn
- Raquel Justice as Kira
- Parker Queenan as Reed
- Millicent Simmonds as Libby
- Main article: Episode Guide
- 10/08/18 - The Boys Are Back (301)
- 10/15/18 - Howling at the Moon Festival (302)
- 10/22/18 - It's a Dilemna (303)
- 11/02/18 - Hole in the Wall (304)
- 11/09/18 - That Syncing Feeling (305)
- 11/16/18 - Cookie Monster (306)
- 11/30/18 - The New Girls (307)
- 01/18/19 - I Got Your Number (308)
- 01/25/19 - Secret Society (309)
- 02/01/19 - The Quacks (310)
- 02/08/19 - One in a Minyan (311)
- 02/22/19 - The Ex Factor (312)
- Starting with this season, Trent Garrett who plays Bowie has been promoted to a series regular.
- The updated intro was released on September 24, 2018, making Andi Mack the seventh series to have a new or updated sequence for the third season after Hannah Montana, A.N.T. Farm, Girl Meets World, K.C. Undercover, Bunk'd and Bizaardvark.
- This is the last season with Stoney Westmoreland as Ham Mack, following his arrest and criminal charges. Starting with I Got Your Number, all episodes featuring him were edited to remove his character.