Big Little Lies Season 3 Will Adapt Big Little Truths With Major Changes

Big Little Lies Season 3 is moving forward with a new story and a new book to guide it.

Liane Moriarty’s recently released novel, Big Little Truths, will provide the foundation for the third season of HBO’s hit drama. However, readers should not expect the television series to follow the sequel page for page.

Moriarty told People that the show’s producers have read the book, but she is “absolutely sure there will be huge changes” when it is adapted for television.

Those changes may be unavoidable. The HBO series has already created its own version of the story, including an entire second season that did not directly adapt a Moriarty novel. Big Little Truths, meanwhile, continues from the original book rather than attempting to reconcile every decision made by the show.

Here is what readers and viewers should know about the upcoming season, its source material and why Big Little Truthsmay look very different on the screen.

Big Little Truths Will Be the Basis for Big Little Lies Season 3

Published on August 25, 2026, Big Little Truths is Moriarty’s first direct sequel to one of her novels. It brings back Madeline, Celeste, Jane, Renata and Bonnie approximately 10 years after the events of Big Little Lies.

Their children, who were beginning elementary school in the original story, are now teenagers dealing with high school, relationships, alcohol, drugs and secrets of their own.

According to the official synopsis from Penguin Random House, trouble begins when the high school principal receives a threatening package. A mysterious stranger also starts appearing around the school and asking seemingly innocent questions.

As the community becomes increasingly unsettled, the five women must confront the long-term consequences of the truths they have and have not shared with their children.

The decade-long time jump makes the book a natural source for Season 3. It allows the television series to acknowledge the years that have passed since the second season aired in 2019 while giving both the mothers and their children new problems to face.

Moriarty described the third season as being in “active, enthusiastic development” and said she hopes filming can begin sooner rather than later. HBO has not announced a production date or premiere date.

Why Season 3 Could Be Very Different From the Book

The largest challenge facing the adaptation is that the books and the HBO series no longer share exactly the same continuity.

Moriarty’s original Big Little Lies novel takes place in Australia, while HBO relocated the story to Monterey, California. The first season also made changes to the characters and ending while retaining the central mystery and most important emotional arcs.

Season 2 moved even further beyond the original source material. It continued the aftermath of Perry Wright’s death and ended with Bonnie and the other women entering a police station, apparently ready to reveal what happened.

Moriarty took a different approach while writing Big Little Truths. She did not attempt to make the sequel conform to everything that happened in the television adaptation.

“I had no problem ignoring the plot of the show,” she told The Hollywood Reporter.

That creates an interesting challenge for Season 3. The writers can use the sequel’s central mystery, teenage characters and family conflicts, but they will also need to account for the show’s Season 2 ending.

The adaptation could therefore become a combination of two stories: the aftermath of Bonnie’s apparent confession and the new high-school mystery introduced in Big Little Truths.

Liane Moriarty Will Take a Hands-Off Approach

Although her new novel will inspire the season, Moriarty does not plan to become closely involved in adapting it.

The author explained that working on previous screen adaptations taught her how difficult it can be to separate the needs of a book from those of a television production. When a production changes something that affects the wider story, her instinct is naturally to return to the solution she already developed in the novel.

For Season 3, she wants to step back and experience the finished series as a viewer.

When Moriarty decided to write Big Little Truths, she informed HBO but did not ask the producers for suggestions. She also did not want feedback about which ideas would or would not work for the series.

“I’ll just give [the manuscript] to you and you can do what you want with it,” Moriarty recalled telling the network, according to Entertainment Weekly.

Her decision should give the show’s creative team room to adapt the material around the established HBO characters. It also allowed Moriarty to write a true sequel to her novel without treating it as a blueprint for a television production.

The New Story Puts the Children at the Center

One of the most promising elements of Big Little Truths is its greater focus on the children.

Moriarty initially resisted writing a sequel because she felt that she had already put the characters through enough turmoil. Her perspective changed when she began developing a separate novel about high school students.

She realized that the teenage story could belong to the children from Big Little Lies.

That decision gives the sequel a reason to exist beyond reuniting its most recognizable characters. Madeline, Celeste, Jane, Renata and Bonnie are no longer simply trying to protect young children. They are raising teenagers who have their own relationships, secrets and understanding of the past.

The time jump should also create opportunities for Season 3 to explore how the events surrounding Perry’s death affected the next generation. The children may not know everything their mothers concealed, but they are old enough to recognize when something is being kept from them.

That tension could become the connection between the book’s new mystery and the unresolved ending of Season 2.

Mary Louise Could Return in Season 3

One of the most intriguing links between the novel and the television series is Mary Louise Wright, Celeste’s mother-in-law.

Meryl Streep introduced the character in Season 2, but Mary Louise did not appear in the original Big Little Lies novel. Moriarty had helped create the character for the show and decided to bring her into Big Little Truths.

In the novel, Celeste becomes concerned about Mary Louise’s increasingly unusual behavior. It is unclear whether her actions are caused by forgetfulness, her characteristically blunt personality or something more threatening.

Mary Louise’s presence in the source material gives Season 3 a clear opportunity to bring Streep back. However, HBO has not officially announced her return.

Moriarty also acknowledged that Laura Dern’s performance influenced how she approached Renata in the new book. After watching Dern turn the character into one of the show’s most memorable personalities, Moriarty expanded Renata’s role in the sequel.

It is a rare example of an adaptation influencing the books that originally inspired it.

Who Is Making Big Little Lies Season 3?

Francesca Sloane, the co-creator and showrunner of Mr. & Mrs. Smith, joined the project in 2025. She is expected to write the Season 3 premiere and executive produce alongside David E. Kelley, Nicole Kidman and Reese Witherspoon.

Kidman and Witherspoon are expected to return as Celeste and Madeline. A complete cast list has not been announced.

Shailene Woodley, Laura Dern and Zoë Kravitz have all previously expressed interest in returning. Woodley celebrated the news that the third season was progressing, but HBO has not confirmed contracts for every member of the Monterey Five.

There is also no announced director, episode count, filming schedule or release date.

What Should Viewers Expect From Season 3?

The central idea of Big Little Truths appears perfectly suited to the series: familiar women, older children, buried secrets and a disturbing new mystery disrupting an affluent community.

Yet the upcoming season cannot simply reproduce the novel. It must continue the television story, address the consequences of the Season 2 finale and adapt characters who have evolved differently on the screen.

That does not make Big Little Truths less important. The novel gives Season 3 its time jump, its teenage perspective and the new crisis that brings the women back together. It may function as the season’s foundation rather than its complete roadmap.

Moriarty’s warning about “huge changes” is therefore less a cause for concern than an acknowledgment that the books and television series have become related but distinct versions of the same world.

Fans can read Big Little Truths now, but they should not assume that doing so will reveal everything that happens in Big Little Lies Season 3.

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