On October 4, 2017, both Nickelodeon and Mace Coronel announced that they had mutually parted ways for Mace to leave the show before they had completed filming the season. Therefore, Dicky Harper, will miss out on the final produced five episodes, unless the production codes get out of order, which would give him a chance to make an appearance on one out of the five final episodes.
On November 6, 2017, Lizzy Greene revealed to fans that a new character named Britt would replace Dicky. Dicky will apparently be taking a little trip to Australia and will therefore be replaced with Britt. He is portrayed by Jonah Hwang.
On December 23, 2017, promos of episodes in Season 4 were started being seen, these episodes were included; Dude, Where's My School?, Wrestle-Mae-nia, Nicky, Ricky, Dicky & BeyDawncé, The Harper Quad-Jobbers, Leader of the Stack, and Quadbusters.
- Lizzy Greene as Dawn Harper (6/6 Episodes)
- Casey Simpson as Ricky Harper (6/6 Episodes)
- Mace Coronel as Dicky Harper (6/6 Episodes)
- Aidan Gallagher as Nicky Harper (6/6 Episodes)
- Allison Munn as Anne Harper (6/6 Episodes)
- Brian Stepanek as Tom Harper (6/6 Episodes)
- Kyla Drew Simmons as Mae Valentine (6/6 Episodes)
- Theodore Barnes as Miles (6/6 Episodes)
- Ariana Molkara as Sadie (5/6 Episodes)
- Sidney Floyd as Brooklyn (4/6 Episodes)
- Hayden Crawford as Dooley (3/6 Episodes)
- Miles Elliot as Kipper (2/6 Episodes)
- Isabella Revel as Avery (2/6 Episodes)
- Rena Strober as Ms. Tassinari (2/6 Episodes)
- Rose Abdoo as Principal Sarah Noonan (1/6 Episodes)
- Siena Ugdong as Natlee (0/6 Episodes)
- Jonah Hawigg as Britt (0/6 Episodes)
- Michael Goodman as Cash (2/6 Episodes)
- Gabrielle Sanalitro as Gladys (1/6 Episodes)
- Tessa Bella as Taylie (1/6 Episodes)
- Maddox Henry as Zayn (1/6 Episodes)
- Paul Vogt as Mr. Wigglesworth
- Carsyn Rosenbaum as Josephine Noonan
- Evan Whitten as Grayson Noonan
- Main article: Episode Guide
These are episodes that have confirmed titles and dates.
- 01/06/18 - Dude, Where's My School? (401)
- 01/13/18 - Wrestle-Mae-nia (407)
- 01/20/18 - Nicky, Ricky, Dicky & BeyDawncé (402)
- 01/27/18 - It's a Hard Knocks Life (403)
- 02/03/18 - Sympathy for the Squishy (404)
- 02/17/18 - The Harper Quad-Jobbers (406)
Below are the confirmed Season 4 episodes, but have not yet been matched up to an air date.
- Leader of the Stack (405)
- Quadentity Crisis (408)
- Quadbusters (409)
- We'll Always Have Parasites (410)
- Quadcodile Dundee (411)
- House Crushing for Dummies (412)
- Quadspiracy Theory (413)
- Lasties with Firsties (414)
- Season 4 was confirmed on March 20, 2017.
- Season 4 is a short-length season with consisting of only fourteen episodes.
- The season is more modern-day than the three other seasons. Similar to The Thundermans.
- Lizzy Greene confirmed they had started filming Season 4 on May 9, 2017 and Aidan Gallagher confirmed they had finished filming on September 20, 2017.
- Mace Coronel mutually parted ways with Nickelodeon and left the show in August 2017. He will not appear in the last five episodes. However, if the episodes do not go into production order, he may appear at least once in the last five episodes.
- On Instagram, Kyla Drew Simmons, Allison Munn and Aidan Gallagher gave hints to it being the final season, with their posts and also stating that Nickelodeon does normally end a show after the show’s fourth seasons.
- Following Mace's exit from the series, many of the cast members including Lizzy and Aidan did post on their social media pages, that they're saying goodbye to their characters, also hinting that it would be the final season.
- Brian Stepanek is the director of the episode, Quadbusters.
- The series finale is scheduled to be Lasties with Firsties.
- Many male characters, including Aidan Gallagher, Casey Simpson, Mace Coronel, Hayden Crawford and Theodore Barnes's voices are deeper, due to them going through puberty.
- Principal Tarian will most likely not appear this season, since he is the principal of Edgewood School; which the Harper Quads left. Another reason why he is not likely to appear in this season, is due to the fact that he is filming as "The King" on the Nickelodeon live action series, Knight Squad.
- The first three recurring characters to be confirmed were Avery, Miles and Natlee. In addition to this, some of the recurring characters from the previous season, Season 3, returned this season, this was also including Dooley.
- There have been six new recurring characters this season, including, Kipper, Sadie, Brooklyn, Ms. Tassinari, Britt and Pricinipal Sarah Noonan.
- After four seasons, consisting of 84 episodes, Nickelodeon announced that along with the other live action series, School of Rock, this would be their final season. The reason that Nicky, Ricky, Dicky & Dawn is ending, is down to the fact that there was a lot of arguments and drama on set. It was said that Casey Simpson and Mace Coronel were bullying Lizzy Greene, this sometimes led to her crying in between takes. They blocked each other on social media and never really talked on set. After this, Mace Coronel was fired before Nickelodeon could order more episodes for this season or add an extra season. They then decided that they should just end the show because the show is not about quads, when it is only featuring three of them.
- On March 27, 2018, Lizzy Greene confirmed that there would be major plot twists in Season 4 and celebrities and guest stars from other Nickelodeon show will be in Season 4.