|1994-1995||The Young and the Restless||Colleen Carlton|
|2006||Malcolm in the Middle||Heidi||Guest|
|2009||Terminator: The Sarah Connor Chronicles||Zoe McCarthy||Guest|
|2009||Grey's Anatomy||Hillary Boyd||Guest|
|2010||First Day||Abby||Recurring; 7 Episodes|
|2012||Park It Up||Brenda||Guest|
|2013-present||The Walking Dead||Tara Chambler||Season 4-Recurring
Season 5- Main
|2014||Men at Work||Mopey Hipster Girl||Guest|
- Masterson is the younger sister of Danny Masterson (Steven Hyde from "That '70s Show"), Jordan Masterson, Christopher Masterson (Francis from "Malcolm in the Middle"), and Will Masterson.
- She built a primary school in Nepal.
- Her half-brother, Christopher Masterson, who starred as Francis on "Malcolm in the Middle", helped Alanna to score a small role on "Malcolm in the Middle".
- She and her fellow cast member Chandler Riggs share the same birthday.
- On July 27 2015, she posted a picture on Instagram, revealing she was pregnant. On November 5 2015, she had the baby, whose gender is a girl and the name is Marlowe.