Harley Quinn has never played by the rules—and loyalty isn’t exactly her superpower. While she’s known for her madcap antics and unpredictable alliances, she’s also left a trail of shock and heartbreak through some of the DC Universe’s most memorable betrayals. From splitting with the Joker to flipping on the Suicide Squad, Harley’s sense of morality is as unstable as her grip on reality. But what makes her betrayals so powerful is that they often come from a place of growth, pain, or twisted justice. Her actions turned heads, broke hearts, and redefined what it means to be bad… or good.
#10: Turning on the Joker in Suicide Squad (2016 Film)
While her romance with the Joker was the backbone of Harley’s origin story, Suicide Squad (2016) gave us the first big-screen hint that Harley was ready to break free. After spending much of the movie pining for her Puddin’, she finally turns her back on him when it counts.
In the climax, Joker’s dramatic rescue is thwarted, and though the film doesn’t go full emancipation, it’s clear Harley begins to see through his manipulation. The seeds of betrayal are planted—and pay off more explosively in later stories. It marked a shift in the public perception of Harley: from sidekick to survivor.
The shock comes not from her betrayal of a villain—but from her betrayal of her own trauma cycle. Walking away from the Joker wasn’t just character development—it was rebellion against everything she was conditioned to love.
#9: Poison Ivy’s Betrayal—And Harley’s Cold Payback
Harley and Ivy have one of the most beloved (and complicated) partnerships in DC. But in Gotham City Sirens, things get messy when Ivy is forced to turn Harley over to the Joker in a moment of psychological manipulation. Harley is captured and briefly reverts to her old, abused dynamic.
But Harley doesn’t stay broken. When she regains control, she confronts both Ivy and Catwoman. While she eventually forgives them, she makes it very clear: if they ever cross her again, she won’t hesitate. Her tone is deadly serious—and uncharacteristically cold.
The betrayal may have started with Ivy, but Harley’s response was the shocker. She didn’t lash out blindly. She thought it through, kept score, and made sure they knew it. It was a warning wrapped in a smile—classic Harley.
#8: Abandoning the Suicide Squad Mid-Mission
Harley Quinn has left the Suicide Squad hanging more than once—but one of the most shocking instances comes in Suicide Squad Vol. 4, when she fakes her death mid-mission to escape Amanda Waller’s control.
The team is knee-deep in a deadly operation when Harley stages a brutal fight with Waller’s agents, vanishes in an explosion, and disappears. No one—not Deadshot, not Boomerang, not even Waller—sees it coming.
What makes this betrayal sting is how personal it feels. Harley had grown into an unlikely glue for the team, forming genuine bonds. Her decision to ghost them, even for freedom, cuts deep—because for once, the Squad trusted her. And she walked away anyway.
#7: Stealing Power from Wonder Woman in Harley Quinn: Black + White + Red
In this alternate take from the digital series Harley Quinn: Black + White + Red, Harley teams up with Wonder Woman on a multiversal mission—only to betray her at the last minute and siphon off a massive power source for herself.
It’s a tongue-in-cheek betrayal that turns into a full-blown crisis. Wonder Woman, believing Harley’s redemption arc was genuine, is blindsided when Harley taps into the artifact’s energy and begins reshaping reality for her own amusement.
While non-canon, the shock of this betrayal lies in how easily Harley deceives someone as perceptive as Diana. It’s a reminder that Harley’s moral pendulum can swing in any direction—and even goddesses can misread her chaotic charm.
#6: Selling Out the Gotham City Sirens
In the Gotham City Sirens finale, Harley shocks both fans and friends when she betrays Catwoman and Poison Ivy to return to the Joker. After months of bonding, fighting alongside them, and building trust, Harley takes everything they’ve worked for and throws it away in a delusional attempt to revive her toxic love.
The betrayal is heartbreaking not because it’s calculated—but because it’s desperate. Ivy and Selina risked everything for Harley’s redemption, and she throws it back in their faces. It’s not the act of a villain—it’s the act of a broken heart, still in denial.
The fallout is severe. Ivy nearly kills her. Selina walks away in disgust. It’s a betrayal that fractures the trio—and shows how deep Joker’s hold on Harley really runs, even when she wants to break free.
#5: Turning on Amanda Waller in Suicide Squad Rebirth
Amanda Waller may have believed she could control Harley Quinn, but in the Suicide Squad: Rebirth era, Harley proves she plays by no one’s rules—not even Waller’s. After years of being used as a living weapon and manipulated through bomb implants, Harley has had enough. In one of the most explosive betrayals in Suicide Squad Vol. 5, she rallies the team and turns on Waller during a black-ops mission.
Harley leads a full-scale rebellion, exposing Waller’s secrets and nearly killing her before stopping short—for now. What makes this betrayal so powerful is that it’s not impulsive—it’s calculated. Harley orchestrates her mutiny with precision, choosing the moment that will hurt Waller most and executing it with terrifying efficiency.
This isn’t Harley snapping—this is Harley evolving. She knows how to hurt the people who hurt her. And this time, she chooses justice over chaos… even if it still involves blowing a few things up.
#4: Betraying Batman’s Trust in Harleen
In the Harleen miniseries by Stjepan Šejić, readers get a deeper, psychological look at Harley’s transformation from Dr. Harleen Quinzel to the Joker’s queen. But the emotional gut punch comes when Batman—who sees her potential and believes in her intelligence—offers her an olive branch early in her descent. He warns her about the Joker, tries to reach her, and shows a rare moment of vulnerability.
And she throws it away.
Rather than heed Batman’s warning, Harleen defends the Joker, justifies his behavior, and ultimately aids in his escape—undermining Batman and her own profession. It’s a betrayal of Gotham’s protector, yes, but more importantly, it’s a betrayal of herself.
This version of Harley doesn’t just fall for the Joker—she rationalizes him, sabotaging her own ideals and ethics. The heartbreak isn’t in watching her fall for a villain—it’s in watching her turn her back on everything she once stood for.
#3: Framing Booster Gold in Heroes in Crisis
In Heroes in Crisis, the shocking deaths at the Sanctuary rehabilitation center ripple through the DC Universe—and at the center of the chaos is Harley Quinn. When several heroes are murdered, Harley pins the blame on Booster Gold, claiming he snapped and went on a killing spree.
What makes this betrayal especially jarring is that Booster and Harley had grown close. They were both broken, vulnerable, trying to recover from trauma. Harley’s accusation leads to a full manhunt, public humiliation, and complete devastation of Booster’s already fragile state.
The twist? Booster didn’t do it—and Harley knew it. While her grief over Poison Ivy’s death is understandable, her willingness to throw Booster under the bus, using her survivor status for manipulation, cuts deep.
This isn’t playful Harley. This is a woman so hurt, so desperate for catharsis, that she sacrifices someone else’s peace to make sense of her own pain. It’s a betrayal that redefines the consequences of Harley’s chaos.
#2: Killing the Joker in Injustice: Gods Among Us
In the Injustice universe, the Joker pushes Superman too far tricking him into killing Lois Lane and nuking Metropolis. Superman kills Joker in a rage. But what many forget is Harley’s response in the aftermath.
Though still psychologically tied to “Mistah J,” Harley ultimately joins Batman’s resistance against Superman’s regime. But the shocking moment comes when Harley is forced to confront Joker’s legacy—literally. In a later flashback, when faced with Joker’s attempt to reassert control over her and the world, Harley does what fans never expected: she kills him.
This betrayal isn’t about shock value—it’s about emancipation. Harley finally severs the final thread of manipulation, choosing justice, independence, and the greater good over love and delusion.
The betrayal of Joker is personal, poetic, and powerful. She was his pawn, his partner, and his punchline. Now? She’s, his executioner. And in that moment, Harley Quinn became something entirely her own.
#1: Betraying Herself in Mad Love
The most devastating betrayal Harley ever commits isn’t against Batman, Ivy, or the Joker—it’s against herself. In the iconic Batman Adventures: Mad Love comic (and its animated adaptation), Harley captures Batman single-handedly, proves herself to Joker, and nearly kills the Dark Knight… only for Joker to arrive, ridicule her, and throw her out a window.
This moment is the pinnacle of tragic irony. Harley finally breaks through the noise, accomplishes what Joker never could—defeating Batman—and instead of being proud, Joker punishes her. And even then? Harley forgives him.
It’s a betrayal of her intelligence, her strength, and her dignity. Not because she’s evil—but because she wants so desperately to be loved. That’s what makes it so heartbreaking. She isn’t evil. She’s hurt. And that hurt makes her betray the person she could be—for the illusion of someone she thought she needed.
Of all her betrayals, this is the most gut-wrenching—because it’s the one that hurts her the most.
Harley Quinn has betrayed teammates, villains, heroes—even herself. But what makes her betrayals so unforgettable isn’t just the chaos—it’s the complexity. Every shocking twist is laced with pain, survival, or wild justice. Whether she’s turning her back on the Joker or burning bridges with the Bat-Family, Harley’s betrayals reveal the truth: behind the laughter is a woman constantly rewriting the rules, even when it breaks her heart. And that’s what makes her one of the most unpredictable—and compelling—characters in the DC Universe.
