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.
- Lizzy Greene as Dawn Harper (23/23)
- Casey Simpson as Ricky Harper (23/23)
- Mace Coronel as Dicky Harper (23/23)
- Aidan Gallagher as Nicky Harper (23/23)
- Allison Munn as Anne Harper (23/23)
- Brian Stepanek as Tom Harper (23/23)
- Kyla Drew Simmons as Mae Valentine (22/23)
- Siena Agudong as Natlee (9/23)
- Theodore Barnes as Miles (12/23)
- Hayden Crawford as Dooley (8/23)
- Isabella Revel as Avery (5/23)
- Sofia Wylie as June (3/23)
- Molly Jackson as Brianna (2/23)
- Jessica Belkin as Madison (1/23)
- Lydia Boland as Molly (1/23)
- Lincoln Melcher as Mack (1/23)
- Madison Hubbard as Emma Kramden (4/23)
- Savannah Hubbard as Jules Kramden (4/23)
- Ethan Kent as George Kramden (4/23)
- Gavin Kent as Lyle Kramden (4/23)
- Mackenzie Ziegler as Lilly (1/23)
- Maddie Ziegler as Eiffel (1/23)
- Spencer Tomich as Trey (3/23)
- Gage Petrone as Franco (3/23)
- 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 this season.
- Kyla Drew Simmons, who portrays Mae Valentine, becomes a main character. She is absent in one episode though - YOCO.
- Mace Coronel's haircut changes to medium-length although 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 scheduling from Season 2 pushed back the Season 3 premiere.
- .Ricky Harper wears similar blue jeans to the ones he wore in Scaredy Dance in the episodes The Wonderful Wizard of Quads, QUADGOALS, and Cementing the Quads' Legacy.
- New recurring characters were seen like Miles, Dooley, Avery, June, Kramden Quads, and Franco.
- Special guest stars were Mackenzie Ziegler, Maddie Ziegler, and Aubrey Witby (The Thundermans).
- Alex and Maia Shibutani are ice dancers, Andrew Newman works on NRDD as a writer, April Audia works as a snack machine in Henry Danger and is the producer of NRDD. Breanna Yde has a lead role in School of Rock, Ricardo Hurtado has a main role in School of Rock, Audrey Whitby has a recurring role on The Thundermans, Noah Urrea is a singer, Buddy Handleson was on Wendell and Vinnie and was also on Bella and The Bulldogs, Jade Pettyjohn has a main role on School of Rock, Tia Mowry was on a show named Tia and Tamera, Gabby Douglas is a olympic gymnastic player, Dana Snyder is on The Thundermans, April Audia is the snack machine in Henry Danger and is the producer on NRDD.
- The most frequent recurring actor to appear was Theodore Barnes as Miles appearing for 12/23 episodes.