7.6/102,206 votes#1 - Girl of Steel
Season 3 Episode 1 - Aired 10/9/2017
Kara deals with the loss of Mon-El by focusing all her energy on being Supergirl and the mysterious new threat against National City. Alex confesses a secret to Maggie about their impending nuptials. A citizen of National City has a mysterious connection to Kara, and Lena makes a bold move.
Director: Jesse Warn
Writer: N/A
7.2/101,925 votes#2 - Triggers
Season 3 Episode 2 - Aired 10/16/2017
Psi, a thief with psychic powers, attacks National City. Able to immobilize people by tapping into their worst fears, Psi proves a formidable opponent for Supergirl. Meanwhile, James and Lena are at an impasse, and Samantha starts her new job at L-Corp.
Director: David McWhirter
Writer: Gabriel Llanas, Anna Musky-Goldwyn
7.2/101,930 votes#3 - Far From the Tree
Season 3 Episode 3 - Aired 10/23/2017
Eliza throws Alex and Maggie a wedding shower, which causes Maggie to reach out to her estranged father. Supergirl joins J’onn on a personal mission.
Director: Dermott Downs
Writer: Jessica Queller, Derek Simon
7.4/101,837 votes#4 - The Faithful
Season 3 Episode 4 - Aired 10/30/2017
Kara investigates a secretive new group whose leader, Thomas Coville, has a mysterious connection to Supergirl. Meanwhile, Samantha feels like she's letting Ruby down, and J'onn confesses an old secret.
Director: Jesse Warn
Writer: Paula Yoo, Katie Rose Rogers
7.4/101,874 votes#5 - Damage
Season 3 Episode 5 - Aired 11/6/2017
When multiple children get sick from lead poisoning, Morgan Edge points the finger at Lena and blames her creation of the lead bomb she made to save National City from the Daxamites. While Lena knows she never intended any harm, she fears there may have been a flaw in her design, leaving her responsible. Kara teams up with Samantha to clear Lena’s name, but it turns out to be harder than they thought. Meanwhile, Alex and Maggie make a crucial decision about the future of their relationship.
Director: Kevin Smith
Writer: Cindy Lichtman, Eric Carrasco
8.1/102,257 votes#6 - Midvale
Season 3 Episode 6 - Aired 11/13/2017
Kara and Alex head home to Midvale for a little R&R. While there, Kara recalls a painful memory of a childhood friend's death and how that traumatic experience brought the Danver sisters closer together.
Director: Rob J. Greenlea
Writer: Caitlin Parrish, Jess Kardos
7.6/101,868 votes#7 - Wake Up
Season 3 Episode 7 - Aired 11/20/2017
When Winn and the team discover an alien ship has crash landed deep underwater beneath National City, Kara/Supergirl is called in to investigate. Meanwhile, Hank attempts to bond with his father, Myr'nn. Samantha, eager for some understanding of the changes she has been experiencing, looks to her estranged mother, Patricia Arias, for answers.
Director: Chad Lowe
Writer: Gabriel Llanas, Anna Musky-Goldwyn
8.7/103,800 votes#8 - Crisis on Earth-X (I)
Season 3 Episode 8 - Aired 11/27/2017
Barry and Iris’s wedding brings the gang together, but things go awry when villains from Earth-X attack the ceremony. All of the superheroes band together with help from their super friends like Citizen Cold, The Ray, Felicity Smoak, Iris West and Alex Danvers to take on their most formidable villains yet. Earth’s mightiest heroes – Green Arrow, Supergirl, The Flash and White Canary – lead their teams into battle to save the world. The crossover continues on Arrow S06E08 Crisis on Earth-X (II), The Flash S04E08 Crisis on Earth-X (III) and DC's Legends of Tomorrow S03E08 Crisis on Earth-X (IV).
Director: Larry Teng
Writer: N/A
8.5/102,201 votes#9 - Reign
Season 3 Episode 9 - Aired 12/4/2017
Supergirl investigates a mysterious symbol popping up all over National City, tracing its origins back to an ancient prophecy and the mark of the World Killer, Reign. Meanwhile, the tension between Lena and Morgan Edge continues to build, causing James to step in and offer up some protection, and possibly igniting a spark in the process.
Director: Glen Winter
Writer: Paula Yoo, Caitlin Parrish
7.7/101,760 votes#10 - Legion of Superheroes
Season 3 Episode 10 - Aired 1/15/2018
Struggling to heal from her injuries inflicted by Reign, Supergirl remains in a dreamlike state, unable to be reached. Mon-El recruits one of the Legion members, Brainiac-5, to try to bring her back. Meanwhile, Reign continues her rampage on the city so the DEO teams up with the Legion of Superheroes to try to stop her.
Director: Jesse Warn
Writer: Derek Simon, Eric Carrasco
7.5/101,690 votes#11 - Fort Rozz
Season 3 Episode 11 - Aired 1/22/2018
As Reign continues to terrorize the city, Supergirl teams up with Saturn Girl, and the two recruit Supergirl’s former enemies, Livewire and Psi, to form a team for a mission to Fort Rozz to recover a prisoner who has information on how to defeat Reign once and for all. Meanwhile, Alex babysits Ruby.
Director: Gregory Smith
Writer: Gabriel Llanas, Anna Musky-Goldwyn
7.2/101,680 votes#12 - For Good
Season 3 Episode 12 - Aired 1/29/2018
Someone tries to kill Morgan Edge and he barely survives. He accuses Lena of being behind the attempt and vows to destroy her. When Lena fears her hatred for Morgan will take her to the Luthor dark side, Kara steps in to help her friend. Meanwhile, after Sam realizes she’s losing time, she confides in Alex who decides to run some medical tests to see if she can find out what’s going on with her new friend.
Director: Tawnia McKiernan
Writer: N/A
7.3/101,646 votes#13 - Both Sides Now
Season 3 Episode 13 - Aired 2/5/2018
The DEO captures a second Worldkiller, Purity. Supergirl and Alex use very different methods of interrogation with Purity in the hopes of finding out how to defeat Reign. However, Purity escapes and attacks the city’s subway tunnels. Meanwhile, J’onn, Winn and Mon-El band together to fix the Legion ship.
Director: Jesse Warn
Writer: Paula Yoo, Jessica Queller
7.0/101,601 votes#14 - Schott Through the Heart
Season 3 Episode 14 - Aired 4/16/2018
When Winn’s father dies, his estranged mother, Mary, reappears trying to reconnect and to explain why she abandoned him all those years ago. Winn is too embittered from his rough childhood to forgive her but when a copycat Toyman attacks, the two must work together to stop him. Mon-El tells Kara something important about the Worldkillers, and Alex becomes suspicious of Myr'nn’s recent behavior.
Director: Glen Winter
Writer: Derek Simon, Caitlin Parrish
7.5/101,572 votes#15 - In Search of Lost Time
Season 3 Episode 15 - Aired 4/23/2018
Myr'nn inadvertently causes psychic disturbances at the DEO; Supergirl must work with J'onn to contain the chaos; Mon-El begins training Kara in fighting techniques he's learned in the future.
Director: Andi Armaganian
Writer: N/A
7.4/101,510 votes#16 - Of Two Minds
Season 3 Episode 16 - Aired 4/30/2018
Supergirl and Imra have different ideas on how to stop the third Worldkiller, Pestilence. However, when both Alex and Winn are seriously injured by Pestilence, Supergirl and Imra team up to stop the destruction.
Director: Alexandra La Roche
Writer: Gabriel Llanas, Anna Musky-Goldwyn
7.5/101,535 votes#17 - Trinity
Season 3 Episode 17 - Aired 5/7/2018
Still reeling after learning about Lena’s secret, Supergirl asks Guardian for a favor that could alter his relationship with Lena forever. Meanwhile, with all three Worldkillers united, Supergirl and the team brace for an epic battle.
Director: Caitlin Parrish, Erica Weiss
Writer: N/A
7.5/101,468 votes#18 - Shelter from the Storm
Season 3 Episode 18 - Aired 5/14/2018
When Reign starts hunting Ruby, Supergirl and Alex work together to keep her safe. Supergirl and J'onn look to Sam’s mother for advice on how to stop Reign and come away with some shocking news.
Director: Antonio Negret
Writer: N/A
6.9/101,507 votes#19 - The Fanatical
Season 3 Episode 19 - Aired 5/21/2018
When Tanya, a disciple of Coville's, escapes from what's left of his cult, she gives Kara and James a journal that could hold the key to saving Sam. Someone learns Guardian's identity and threatens to expose James if he doesn't do what they ask. James contemplates what it means to be a black vigilante without a mask in America.
Director: Mairzee Almas
Writer: Paula Yoo, Eric Carrasco
7.3/101,497 votes#20 - Dark Side of the Moon
Season 3 Episode 20 - Aired 5/28/2018
Supergirl is stunned to discover that a part of Krypton survived. Meanwhile, Alex is attacked while out with Ruby, and Lena considers how far she will go to keep Reign contained.
Director: Hanelle M. Culpepper
Writer: Derek Simon, Katie Rose Rogers
6.4/101,708 votes#21 - Not Kansas
Season 3 Episode 21 - Aired 6/4/2018
Kara makes a major life decision. Meanwhile, J'onn finds out that special DEO-caliber guns have hit the streets of National City.
Director: Dermott Downs
Writer: Gabriel Llanas, Anna Musky-Goldwyn
7.3/101,420 votes#22 - Make It Reign
Season 3 Episode 22 - Aired 6/11/2018
Supergirl learns the true depth of Serena's nefarious plans for Earth. Supergirl, Mon-El and Alura must devise a plan to stop her before Serena gets to Earth. J'onn prepares to say goodbye to his father.
Director: Armen V. Kevorkian
Writer: Cindy Lichtman, Ray Utarnachitt
7.5/101,518 votes#23 - Battles Lost and Won
Season 3 Episode 23 - Aired 6/18/2018
Supergirl and team take on Selena in an epic battle for Earth.
Director: Jesse Warn
Writer: Robert Rovner, Jessica Queller
The Best Episodes of Supergirl Season 3
Every episode of Supergirl Season 3 ranked from best to worst. Discover the Best Episodes of Supergirl Season 3!
Twenty-four-year-old Kara Zor-El, who was taken in by the Danvers family when she was 13 after being sent away from Krypton, must learn to embrace...
Genres:DramaSci-Fi & FantasyAction & Adventure
Season 3 Ratings Summary
"Girl of Steel" is the best rated episode of "Supergirl" season 3. It scored 7.6/10 based on 2206 votes. Directed by Jesse Warn and written by N/A, it aired on 10/9/2017. This episode is rated 0.4 points higher than the second-best, "Triggers".