Superman/Batman, also known as Batman/Superman, is a monthly American comic book series published by DC Comics and featuring the publisher's two most popular superheroes: Superman and Batman. Superman/Batman premiered in August 2003, an update of the previous series, World's Finest Comics (1941–1986), in which Superman and Batman regularly joined forces.

Superman/Batman explores the camaraderie, antagonism, and friendship between its title characters. Jeph Loeb, the series' first writer, introduced a dual-narrator technique to present the characters' often opposing viewpoints and estimations of each other, which subsequent series writers have maintained. Prior to the events of Batman and the Outsiders #1 (1983), the two iconic characters were depicted as the best of friends. Frank Miller's landmark series The Dark Knight Returns subsequently depicted the heroes as adversaries in a future timeline. This dynamic became standard with John Byrne's The Man of Steel, a Superman reboot published in 1986.

After the first 13 issues, most of the story arcs were independent and self-contained from the ongoing or crossover storylines in the other Batman and Superman comic titles. Superman/Batman #26, Loeb's final issue, features a story written by his son Sam, who died from cancer prior to its release. Twenty-six writers and artists who knew Sam worked on the issue, donating fees and royalties to the Sam Loeb College Scholarship Fund.Newsarama.com: Jeph Loeb on "Sam's Story"

As part of The New 52, a series titled Batman/Superman was released from 2013 to 2016. A second Batman/Superman series was released in August 2019, with issue #16 as part of DC's Infinite Frontier.Batman/Superman #16 (March 23, 2021)

A new ongoing series by Mark Waid titled Batman/Superman: World's Finest was released in March 2022.

Superman/Batman (2003-2011) Jeph Loeb Jeph Loeb, who wrote Superman for two years before the launch of the title, wrote the book for the first two years of its publication. Unlike later writers, Loeb's work on the book lasted for several storylines, which were interconnected.

In the first story arc, "The World's Finest", also referred to as "Public Enemies" (issues #1–6, illustrated by Ed McGuinness), then-U.S. President Lex Luthor declares Superman and Batman enemies of the state, claiming that a Kryptonite asteroid headed for Earth is connected to an evil plot by Superman. Luthor offers a $1,000,000,000 bounty, which encourages both supervillains and superheroes to attack. Superman almost kills Lex, with Batman standing aside. Superman changes his mind at the last moment. The new Toyman, Hiro Okamura, assists with the asteroid's destruction. Captain Atom is seemingly killed.Captain Atom is actually transported to the Wildstorm Universe, as revealed in Captain Atom: Armageddon #1 (December 2005). The danger averted and Luthor's plans in jeopardy, Luthor injects himself with a mixture of Venom and synthetic Kryptonite, dons a battle suit from Apokolips, and confronts Batman and Superman. Luthor is defeated and appears to die in the battle, although he is shown to survive. In the course of the fight, Luthor is exposed to the world as a villain for the first time in post-Crisis continuity.Many of Luthor's crimes were revealed by Lois Lane and the Daily Planet in Action Comics #700 (June 1994). However, the charges against him were dismissed at trial, after he presented falsified evidence that he had been kidnapped by renegade scientists from Cadmus Labs and replaced with a violent clone in Action Comics #737 (September 1997). Losing the presidency, Luthor is succeeded in office by Pete Ross.

In "Protégé" (issue #7, illustrated by Pat Lee), Superboy and Robin investigate Toyman for their mentors.

In "The Supergirl from Krypton" (issues #8–13, illustrated by Michael Turner), the Kryptonite asteroid is revealed to hold a pod that contains Superman's cousin Kara Zor-El. Batman says her arrival is too coincidental. Wonder Woman abducts Kara to Themyscira to train her for combat. Darkseid kidnaps Kara, intending her to be the new leader of the Female Furies. She is rescued from Darkseid and taken back to Earth. The villain follows, seemingly killing Kara at the home of Jonathan and Martha Kent. An enraged Superman throws Darkseid into the Source, entrapping him. However, Kara is back in Themyscira and is introduced to the world as Supergirl. This story arc marked the only time in Michael Turner's career that he provided interior art for a company other than Top Cow Productions or his own publisher, Aspen Comics. The story was dedicated to Christopher Reeve, who died during the year the storyline ended.

In "Absolute Power" (issues #14–18, illustrated by Carlos Pacheco), Legion of Super-Villains members Lightning Lord, Saturn Queen, and Cosmic King eliminate members of the Justice League of America, except for young Superman and Batman, whom they raise as their own children. Batman and Superman are raised to be dictators of the world, eliminating all opposition and killing people who would otherwise be their friends. During a fight with Wonder Woman and the Freedom Fighters, as Uncle Sam has been given Hal Jordan's power ring, during which Batman is killed but Superman is able to kill Diana with her lasso, the timeline is thrown into chaos, and the two men travel through alternate timelines. Darkseid makes a deal with them in one reality to send them back through time to stop the supervillains who raised them from altering history. When trying to change Batman's history back, Batman breaks down and shoots Joe Chill – the killer of Thomas Wayne and Martha Wayne. The Legion then team up with Ra's al Ghul to take over the world. Superman and Batman restore history, but the murders they committed haunt them.

Issue #19 (illustrated by Ian Churchill) is a stand-alone backdoor pilot story for the Supergirl series. The issue was later reprinted as Supergirl #0.

In "With a Vengeance!" (issues #20–25, illustrated by Ed McGuiness), Mister Mxyzptlk battles the Joker, who has tricked Bat-Mite out of his powers, using other characters as their pawns. Superman and Batman fight a team of superheroes from an alternate universe called the Maximums (a pastiche of the Ultimates). Keeping the bargain he made in "Absolute Power", Superman frees Darkseid from the Source Wall. Double-crossed, Superman becomes stuck in the wall himself. Bizarro and multiple Supergirls rescue him. Everyone so far and many more other duplicates fight in an arena before Bat-Mite escapes. The two imps tie up all loose ends with their cosmic powers. Additionally, Superman, Batman and the Toyman discover that Captain Atom is alive.

Mark Verheiden Superman writer and Smallville producer Mark Verheiden took over Superman/Batman with issue #27.

In "Never Mind" (issue #27, illustrated by Kevin Maguire), The Superman and Batman of Earth-Two discover that their minds have been transferred by the Ultra-Humanite and the original Brainwave into the bodies of Power Girl (Superman's cousin) and the Huntress (Batman's daughter). If they cannot reverse the process in time, the women's personalities will reassert themselves and destroy the men's consciousness, killing them.

In "The Enemies Among Us" (issues #28–33, illustrated by Ethan Van Sciver for Parts 1–3, with Matthew Clark picking up Parts 4–5 and Joe Benitez concluding with Part 6), Superman, Martian Manhunter and other alien superheroes are being controlled by an entity known as Blackrock, which later infects Batman when he takes the rock to successfully stand up to Superman. After Superman visits Lois Lane to be reminded why he fights for Earth, he is able to force Blackrock to leave Batman by convincing it that he will kill his friend to spare him being used by the rock. Tracking Blackrock to its source, they discover that it was actually being 'led' by Despero, who convinced an alien race that Earth was not worth saving by giving them access to Superman's mind during a period of self-doubt. Challenging the aliens to read his mind again, Superman convinces them that they were wrong about Earth.

In "A.I." (issues #34–36, illustrated by Pat Lee), Superman and Batman are introduced to Will Magnus and his malleable, shape-shifting Metal Men for the first time (in Post-Infinite Crisis continuity). Bruce Wayne hires the Metal Men as security guards. They go on a rampage and steal a prototype OMAC unit.

Alan Burnett Known for his work on the DC Animated Universe and The Batman television series, Alan Burnett took over as writer of the series with issue #37.

In "Torment" (issues #37-42, illustrated by Dustin Nguyen), Superman is psychologically tortured by the Scarecrow and brought to the war planet Tartaros by DeSaad. DeSaad plants a mind-controlling spike in Superman's head, and sends him to retrieve Highfather's staff from the Source, which Darkseid plans to use to restore his powers. Batman comes after Superman, but is sidetracked by Bekka. Both are unable to control their attraction to one another. Superman retrieves the staff, but is trapped in the Source Wall as a result. Batman and Bekka take advantage of DeSaad's attempted betrayal of Darkseid to steal the staff and bring back Superman. Darkseid and DeSaad flee, and Tartarus is pulled into the hole Superman made in the Source when he escaped. Superman, Batman and Bekka return to Earth, bringing Scarecrow with them. Bekka is retrieved by Orion, and is later seen being killed by a shadowy assailant.

Dan Abnett and Andy Lanning The team of Dan Abnett and Andy Lanning filled in for issue #43, and later wrote off of scripts from Mike Johnson for issues #57–59.

In "Darklight" (issue #43, illustrated by Mike McKone), Doctor Light infiltrates a dark matter fuel experiment on a Waynetech satellite, by creating solidgram versions of the original Teen Titans to distract the guards. He then uses the experiment's Kryptonian processor to enter the Fortress of Solitude. While Superman battles the Titan solidgrams, Batman manages to head off and defeat Light by trapping him in a Dark Matter crystal. Light is later freed by Lex Luthor, who wants him to join his new Injustice League.

In "Nanopolis" (issues #57–59), the Prankster tricks Superman and shrinks him to microscopic size. Batman must find him and return him to normal size. Before returning to normal, the two heroes must rescue the microscopic civilization whose existence has been inadvertently endangered by the Prankster.

Mike Johnson and Michael Green As of issue #46, Mike Johnson joined with Michael Green to continue the series; issue #44 was the beginning of the new run. They are the first writers to hold regular roles on this series since Jeph Loeb.