Acts of revenge are regular occurrences in the plot and character arcs of Lost. In many cases, a wrong committed begins a new arc for a character, as they try to avenge their loss.

Occurrences
The following occurrences of revenge happened in Lost, sorted by character and episode order.
Ana Lucia Cortez

- Before the crash, Ana Lucia murdered Jason McCormack in cold blood in a dark alley for shooting her and killing her unborn child. ("Collision")
Benjamin Linus
- Ben killed his father in the Purge for his bad parenting. ("The Man Behind the Curtain")
- After Keamy killed Ben's adopted daughter, Alex, Ben summoned the smoke monster to attack the mercenary team, and then later declared to Charles Widmore that he would kill his daughter Penny. ("The Shape of Things to Come") He also stabbed Keamy to death when they met in the Orchid. ("There's No Place Like Home, Part 2") When Ben finally confronted Penny, the appearance of her son Charlie Hume stopped Ben from killing her. ("Dead Is Dead") Ben killed Widmore in front of The Man in Black. ("What They Died For")
- Also Ben helped with Sayid's revenge mission against Charles Widmore by ordering him to kill Widmore's associates. This could also have been part of Ben's revenge against Widmore for Alex's death.
Boone Carlyle
- Boone wanted revenge on Locke because he thought he saw his sister die at the hands of the Smoke Monster during a hallucination caused by Locke. The experience helped Boone deal with his feelings for Shannon. ("Hearts and Minds")
Cassidy Phillips
- Cassidy thought that she and Sawyer were involved in a relationship, but she was actually the victim of a con ("The Long Con"). She would get her revenge by pressing charges against him, sending him to prison ("Every Man for Himself").
Charlie Pace

- Charlie shot and killed Ethan Rom for kidnapping Claire, killing Scott, and terrorizing the camp. ("Homecoming")
- Charlie assisted Sawyer in his "long con" against the camp to make Locke "look like a fool", following his treatment of Charlie in "Fire + Water". ("The Long Con")
Chet
- Chet, wanted revenge on Jack for forcing his sister, Achara, to put a tattoo on him during Jack's visit to Thailand. Chet and his friends beat Jack up and tell him to leave the country ("Stranger in a Strange Land")
Claire Littleton

- Claire sought revenge first on the Others when she thought they took her son, Aaron, by torturing, then killing Justin ("Lighthouse") and then Kate when she was told that it was actually Kate that took him ("There's No Place Like Home, Part 3")("Sundown"). She tried (unsuccessfully) to attack Kate by stabbing her before "Locke" stepped in ("Recon"). She would end up reconciling and leaving the island for good with Kate ("The End").
Derek
- Derek wanted revenge on Desmond after Derek's sister, Ruth, was left by Desmond one week before they were supposed to be married. Derek found and punched Des in the face in a Scottish monastery ("Catch-22").
Desmond Hume

- Desmond was angry after finding out that Kelvin Inman was secretly fixing The Elizabeth to leave the island. Desmond confronted Inman, accidently killing him when Kelvin's head hit the rocks. This was a part of a chain of events that led to the crash of Oceanic Flight 815 ("Live Together, Die Alone, Part 2")
Edward Mars

- The Marshall wanted revenge for Kate escaping his custody ("What Kate Did") and for taunting him by continually calling him ("I Do"). Mars would eventually get his revenge by capturing Kate in Australia. He was bringing Austen back on Oceanic Flight 815 on September 22, 2004, when the plane crashed and Austen escaped. Mars would be euthanized by Jack ("Tabula Rasa").
Harper Stanhope
- Harper Stanhope wanted revenge because her husband, Goodwin, was cheating on her with Juliet for over a year ("One of Us"), ("The Other Woman"). To this date, it is not believed that Harper ever got any revenge on Goodwin or Juliet.
Hugo "Hurley" Reyes
- Hurley did not seek revenge on Michael for shooting Libby ("Two for the Road"), but Michael did use this to his advantage to get Hugo to go with Jack, Kate, and Sawyer into the ambush by the Others ("Live Together, Die Alone, Part 2"). Hurley never sought retribution for Michael's actions.
Jack Shepard

- Jack wanted revenge on Locke for Boone's death ("Do No Harm") because he was not told everything about Boone's condition by Locke when they came back from the jungle ("Deus Ex Machina"). Jack physically confronted Locke at Boone's funeral before Charlie and Sawyer pulled him off ("The Greater Good").
- Jack thought that his father was the new man in Sarah's life after she asked for a divorce. As Jack was calling numbers of Sarah's contacts, Christian's cell phone rings. Jack verbally confronts Christian why Sarah is calling him; he then stalks his father and physically confronts him during an Alcoholics Anonymous meeting, which lands Jack in prison ("A Tale of Two Cities").
Jacob

- Jacob sought revenge on The Man in Black for murdering Mother. He dragged his brother into The Heart of the Island that Mother had told them about and threw his body into it, the Smoke Monster came out ("Across the Sea").
Jin Soo-Kwon
- Jin suspected (correctly) that Michael had taken a Rolex watch that Sun's father gave him to deliver to a client in Los Angeles ("...In Translation"). Jin attacked Michael on the beach before being separated by Sayid and Sawyer. Jin was then handcuffed to a large piece of the plane until Michael "released" him ("House of the Rising Sun").
John Locke
- Locke was angry after Charlie took Aaron from Claire to baptize him. After Locke returned the baby to Claire, Locke repeatedly punched Charlie in the face ("Fire + Water").
Juliet Burke
- Juliet wanted revenge after Jack attacked her in the Hydra Station. After Jack opened the door to let the water in, she decked him ("A Tale of Two Cities").
Kate Austen

- Kate killed her father, Wayne, for abusing her mother. ("What Kate Did")
- Kate shot at the Man in Black as retribution for the deaths of Sun, Jin, and Sayid, eventually killing him after he became mortal. ("The End")
The Man in Black
- The Man in Black, in the form of John Locke, eventually killed Jacob indirectly by assuming Locke's form and convinced Benjamin Linus to stab him. ("The Incident, Part 2")
- The Man in Black killed his Mother, sneaking up on her in her camp and stabbing her to death. ("Across the Sea")
Woo-jung Paik
- Mr. Paik found out about an affair between Sun and Jae Lee, but instead of telling Jin about it, Mr. Paik lied and told him that Jae was stealing from him, demanding that Jin kill Jae Lee to restore the family's honor, indirectly leading to Jae committing suicide. ("The Glass Ballerina")
Nikki Fernandez
- Nikki threw a female Medusa spider at her boyfriend, Paulo, because she (correctly) suspected that he found a bag of diamonds they had taken together. The spider paralyzed Paulo; the female spider's bite attracted an onslaught of male Medusa spiders, one of which bit and paralyzed Nikki. They both were buried alive because everyone was under the assumption they were already dead ("Exposé").
Danny Pickett

- Danny Pickett wanted revenge on the Losties -- particularly Sawyer -- because his wife, Colleen, was shot by one the Losties - Sun, on The Elizabeth ("The Glass Ballerina") Pickett would later beat up Sawyer on Hydra Island ("Every Man for Himself"), but was eventually shot by Juliet ("Not in Portland").
Sami

- Sami imprisoned and tortured Sayid for torturing his wife while he served in the Republican Guard. He lured Sayid by saying that he needed a new cook for his restaurant that he owned. ("Enter 77")
James "Sawyer" Ford
- A large portion of James' life was spent looking for the original "Sawyer", who caused his father to kill himself and his mother. When James finally discovered the real Sawyer, Anthony Cooper, he strangled him to death. ("The Brig"). He also killed Frank Duckett, believing him to be Sawyer, in his quest for revenge. ("Outlaws")
- Sawyer sought revenge on a boar for ransacking his tent. ("Outlaws")

- Sawyer revealed Kate's fugitive status to the Flight 815 survivors for trying to steal his place on the raft. ("Born to Run")
- Sawyer conned the survivors and stole the guns partly in revenge for Jack stealing his medicine and for the survivors stealing his stuff while he was on the raft. ("The Long Con")
- He killed Tom Friendly as revenge for kidnapping Walt. ("Through the Looking Glass, Part 1")

- "LaFleur" wanted revenge when Phil punched Juliet in the face ("Follow the Leader") after it was discovered that he helped with the disappearance of young Ben ("Whatever Happened, Happened"). Sawyer actually came close to losing his life to Phil at the Swan site in 1977, as Phil confronted an unarmed LaFleur, only to be impaled by metal scaffolding ("The Incident, Part 2").
- Sawyer beat up Jack after the plan to detonate Jughead in the hole that would eventually become the Swan backfired and Juliet was killed ("LA X, Part 1"). He would also threaten to kill Jack to Kate, only to back off that statement, stating "he deserves to suffer on this rock just like the rest of us." ("LA X, Part 2")
Sayid Jarrah
- Sayid's torturing of Sawyer seemed to be mainly an act of revenge, since Sayid believed Sawyer to be the one who knocked him unconscious while he attempted to get a signal for the transceiver.
- Sayid tried to kill Ana Lucia in revenge for Shannon's death, although he later forgave her for what she did.
- Sayid blamed the the Others for Shannon's death, and went to great lengths to get revenge on them. His torturing of Ben seemed to be mainly out of revenge for what the Others had done to the survivors.
- Sayid turned Michael into the Captain because of his betrayal of the survivors on the island.
- Sayid killed Ishmael Bakir, Peter Avellino, Ivan Andropov, and other associates of Charles Widmore to avenge the death of his love Nadia. ("The Shape of Things to Come") ("The Economist") ("He's Our You")
- Revenge was arguably a factor in Sayid's shooting of a young Benjamin Linus]] in 1977. ("He's Our You")
Shannon Rutherford

- Shannon almost killed Locke, whom she blamed for Boone's death, but Sayid intervened. ("The Greater Good")
Sun Hwa Kwon
- Sun was upset after Juliet told Jin that she had an affair in hopes of keeping Jin and Sun from going with Locke. Sun slapped Juliet, but Jin and Sun did not go with Locke ("Ji Yeon").
Charles Widmore
- Widmore was once in control of the island, but because he had a relationship and family with a person off the island, he was exiled from the island ("Dead Is Dead"). Widmore would spend years trying to return, which he did ("Dr. Linus"), only to be killed by his long time rival, Ben ("What They Died For").
Other references
- One of the pinball machines in the Barracks recreation room is the 1999 "Revenge From Mars".