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 of the season.
- Lizzy Greene as Dawn Harper (4/4 Episodes)
- Casey Simpson as Ricky Harper (4/4 Episodes)
- Mace Coronel as Dicky Harper (4/4 Episodes)
- Aidan Gallagher as Nicky Harper (4/4 Episodes)
- Allison Munn as Anne Harper (4/4 Episodes)
- Brian Stepanek as Tom Harper (4/4 Episodes)
- Kyla Drew Simmons as Mae Valentine (4/4 Episodes)
- Theodore Barnes as Miles (4/4 Episodes)
- Zachary Friedman as Snotty Scotty (3/4 Episodes)
- Ariana Molkara as Sadie (3/4 Episodes)
- Sidney Floyd as Brooklyn (3/4 Episodes)
- Hayden Crawford as Dooley (2/4 Episodes)
- Isabella Revel as Avery (1/4 Episodes)
- Miles Elliot as Kipper (1/4 Episodes)
- Gabrielle Sanalitro as Gladys (1/4 Episodes)
- Katlie Molinaro as Karyn (1/4 Episodes)
- Rena Strober as Ms. Tasinari (1/4 Episodes)
- Michael Goodman as Cash (1/4 Episodes)
- Maddox Henry as Zayn (1/4 Episodes)
- Siena Agudong as Natlee (0/4 Episodes)
- Julie Chang as Reporter (Dude, Where's My School?)
- Winston James Francis as Big Bad Baby Boy (Wrestle-Mae-nia)
- Shane Hartline as The Dentist (Wrestle-Mae-nia)
- Lacey Von Erich as Ms. Purr-Fect (Wrestle-Mae-nia)
- April Audia as Announcer (voice) (Wrestle-Mae-nia)
- Grant Knooche as Liam (Nicky, Ricky, Dicky & BeyDawncé)
- 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.
- 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 this it would be the final season.
- The series finale is scheduled to be Lasties with Firsties.
- Many male character, including Aidan Gallagher, Casey Simpson, Mace Coronel, Hayden Crawford and Theodore Barnes's voices got 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.
- 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 five new recurring characters this season, including, Kipper, Sadie, Brooklyn, Snotty Scotty and Gladys.
- 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 was ending was because, usually Live Action series’ after their fourth season end, after a long good run of around ninety episodes, there are not many more ideas and they have other shows to focus on.