Season 3 was announced on February 9, 2016. The season premiered on January 7, 2017 and ended on August 5, 2017.
In this season, the Harper Quads face a new set of quadruplets, the adorable Kramden Quads. Unlike the Harpers who have nothing in common, the Kramdens have everything in common, look alike and work in harmony. The Harper Quads also undergo major growths this season with graduation from Edgewood School and Dawn and Dicky going through puberty. The quads also make new friends including Miles, Dooley and Avery.
On several occasions this season, the quads are forced to face reality about their reputation that they are selfish and have the tendency to ruin things they're involved with.
- Aidan Gallagher as Nicky Harper
- Casey Simpson as Ricky Harper
- Mace Coronel as Dicky Harper
- Lizzy Greene as Dawn Harper
- Allison Munn as Anne Harper
- Brian Stepanek as Tom Harper
- Kyla Drew Simmons as Mae Valentine
- Siena Agudong as Natlee
- Theodore Barnes as Miles
- Hayden Crawford as Dooley
- Isabella Revel as Avery
- Amahri Richard as Xander
- Sofia Wylie as June
- Molly Jackson as Brianna
- Jessica Belkin as Madison
- Lydia Boland as Molly
- Lincoln Melcher as Mack
- Madison Hubbard as Emma Kramden
- Savannah Hubbard as Jules Kramden
- Ethan Kent as George Kramden
- Gavin Kent as Lyle Kramden
- Mackenzie Ziegler as Lilly
- Maddie Ziegler as Eiffel
- Spencer Tomich as Trey
- Gage Petrone as Franco
- 01/07/17 - Quad With a Blog (301)
- 01/14/17 - Odd Quad Out (302)
- 01/21/17 - Keeping Up With the Quadashians (303)
- 01/28/17 - The Great Mullet Caper (304)
- 02/04/17 - Quadsled (305)
- 02/11/17 - Ye Olde Hand Holde (309)
- 03/18/17 - What's the Worst That Quad Happen? (310)
- 03/25/17 - To Be Invited or Not to Be (313)
- 04/08/17 - Ele-Funk in the Room (307)
- 04/15/17 - Tween Wolf (308)
- 04/22/17 - This Little Piggy Went to the Harpers (306)
- 04/29/17 - I Want My Mae B. Back (311)
- 05/06/17 - The Buffa-Lowdown (314)
- 05/13/17 - Quadshank Redemption (320)
- 05/20/17 - Not-So-Sweet Charity (318)
- 06/03/17 - One Quadzy Summer (319)
- 06/10/17 - Quad for Teacher (316)
- 06/17/17 - Quadpendence Day (315)
- 07/08/17 - Cementing the Quads' Legacy (323)
- 07/15/17 - QUADGOALS (312)
- 07/22/17 - A Space Quadyssey (317)
- 07/29/17 - YOCO (324)
- 08/05/17 - The Wonderful Wizard of Quads (321-322)
- This season had previews of episodes from September to November that would later premiere in January.
- The theme song changed this season.
- Matt Fleckenstein left the show from this season.
- Kyla Drew Simmons, who portrays Mae Valentine, becomes a main character. She is absent in one episode though - YOCO.
- Mace Coronel's voice got deeper due to his puberty between Season 2 and Season 3 production.
- This season was ordered for 14 episodes on February 9, 2016, by Nickelodeon.
- Production for this season was from April 26, 2016 to February 10, 2017.
- A new café from Get Sporty is introduced due to the episode Quad With a Blog where the old café burned down.
- The episode The Great Mullet Caper was the 50th episode produced.
- This season ended exactly one year after Season 2.
- This season only aired for eight months; as the schedulling from Season 2 pushed back the Season 3 premiere.