Most of the cast returned from the first film, including Julie Andrews, Anne Hathaway, Héctor Elizondo, Heather Matarazzo, and Larry Miller. Garry Marshall returned to direct and Debra Martin Chase to produce. New characters include Viscount Mabrey (John Rhys-Davies), Lord Nicholas Devereaux (Chris Pine), and Andrew Jacoby (Callum Blue).
Despite generally negative reviews from critics, the film had a worldwide box office of $122 million.
Five years after the previous events, Mia Thermopolis has just graduated from Princeton University's Woodrow Wilson School and is returning to Genovia with her bodyguard, Joe. There, she will await her reign once her grandmother, Queen Clarisse, steps down as Queen. During Mia's twenty first birthday party, she dances with all the eligible bachelors in hope of finding a husband. She becomes attracted to a handsome gentleman named Nicholas. During the course of the night, Mia's tiara falls off and is caught by a Member of Parliament, Viscount Mabrey, who secretly plans to steal Mia's crown. While the Parliament is in-session the next morning, Mia stumbles upon a hidden room that allows her to secretly listen in. Viscount Mabrey reveals his nephew, Lord Devereaux, is another heir to the Genovian throne. Despite Queen Clarisse's objection, the only way Mia can assume her duties as Queen is if she marries within the month. Clarisse invites Lord Devereaux to stay at the palace, while Mia is shocked to discover Lord Devereaux is actually Nicholas. Mia's best friend, Lilly Moscovitz, surprises her by visiting. Together, they pick through potential husbands. Mia eventually chooses Andrew Jacoby, Duke of Kenilworth, and days later, they are engaged. Mabrey plans to have Nicholas woo Mia and dissolve the engagement.
For a ceremony, Mia is to ride sidesaddle, but is inexperienced. Queen Clarisse provides an ancestral wooden leg decoy to make it look like she's riding sidesaddle. Mabrey spooks Mia's horse with a rubber snake, and Joe rushes to aid Mia, but accidentally tears off the wooden leg. Humiliated, Mia flees to the stables, where Nicholas fails to comfort her. At a garden party, Mia and Nicholas quarrel about Mia's relationship with Andrew; Nicholas tricks Mia into admitting she doesn't love Andrew. Frustrated, she argues, but instead gets bombarded by a kiss. At first, she kisses him back but then backs away. Nicholas pursues her even more, which causes both of them to fall into a fountain. Queen Clarisse finally tells Mia that her behavior with Nicholas needs to stop.
During the Genovian Independence Day parade, Mia sees some boys harassing little girl, and abruptly halts the parade to comfort the girl. Learning that the children are orphans, Mia has a vendor give them all tiaras and lets them walk with her in the parade. Everyone is impressed by her act of generosity, while Mabrey sees it as a political maneuver. Mia later decides to convert one of the royal palaces into a temporary children's center. That night, Mia has her bachelorette party, where Queen Clarisse surfs on a mattress and sings a duet with Princess Asana, one of Mia's good friends. In the meantime, Mabrey realizes Nicholas has fallen for Mia, but Nicholas says that Mia will never love him. Nicholas comes upon Mia as she is practicing her archery as part of her coronation rites. He helps her succeed in getting the arrow to hit the bullseye, something she had been struggling with. Nicholas then informs Mia that he is leaving, but asks to see her just one more time before he goes. She declines, saying she is under close guard.
That night, Nicholas appears outside Mia's window and asks her to come out. Lilly encourages her to go, and Mia sneaks out. They ride out to a lake where they share secrets, dance, and eventually fall asleep. They awaken to find a man in a boat videotaping them. Mia thinks Nicholas set her up, while he insists he had no idea. By the time Mia returns to the palace, the scandalous footage is already being broadcast. Andrew is disappointed and kisses Mia to see if there is a romantic spark between them. They realize that they do not love each other, but do not call off the wedding for the good of Genovia. The wedding is to take place the following day, and Mia's mother, Helen comes with her new husband, Patrick and their newborn son, Trevor. Nicholas decides against attending, but his surly housekeeper, Gretchen informs him that Mabrey engineered their televised scandal.
Before the wedding, Joe informs Mia that Nicholas is innocent. Queen Clarisse encourages Mia to follow her heart, something she has never done and has now cost her Joe, the only man she truly loved. Mia reenters the church, and after pointing out how her grandmother has ruled Genovia while unmarried for a number of years, she tells the members of parliament in the audience to consider the significant women in their lives and questions if they would have them do what they're trying to force her to do (marry someone she does not love). Mabrey cites the law again and once again suggests that his nephew be named King, but just then, Nicholas not only refuses the crown, but also disowns Mabrey as his uncle. Mia proposes the law on royal marriages be abolished, and the Parliament unanimously gives its assent. Encouraged by Mia to have her own happy ending, Clarisse proposes to Joe and they are promptly married.
About a week later, Mia is preparing for her coronation when Nicholas shows up. He professes his love for Mia on bended knee, and they share a romantic kiss. The next day, Mia is crowned "Her Majesty Amelia Mignonette Thermopolis Renaldi, Queen of Genovia", with all in attendance in the royal palace.
An epilogue shows that Genovian Parliament now allows female members, one of whom is Charlotte. And Queen Mia officially opens the children's home.Anne Hathaway as Princess/Queen Amelia "Mia" Thermopolis Renaldi
Julie Andrews as Queen Clarisse Renaldi
Héctor Elizondo as Joe
John Rhys-Davies as Viscount Mabrey
Heather Matarazzo as Lilly Moscovitz
Chris Pine as Nicholas Devereaux
Callum Blue as Andrew Jacoby
Raven-Symoné as Princess Asana
Kathleen Marshall as Charlotte Kutaway
Jonny Blu as himself
Tom Poston as Lord Palimore
Joel McCrary as Prime Minister Motaz
Kim Thomson as Reporter Elsie Kentworthy
Larry Miller as Paolo Puttanesca
Caroline Goodall as Helen Thermopolis O'Connell
Meredith Patterson as Lady Elissa
Spencer Breslin as Prince Jacques
Tracy Reiner as Lady Anthony
Paul Vogt as Lord Crawley
Paul Williams as Lord Harmony
Peter Allen Vogt as Mr. Crawley
Anna Netrebko as herself
Abigail Breslin as Carolina, the orphan child
Hannah Schneider as Dancing Princess Hannah
Charlee Corra Disney as Princess Charlee
Aimee Adams Hall as Princess Aimee
Nadege August as Princess Nadege
Claudia Katz Minnick as Freda Kout
Stan Lee as Three Stooges wedding guest
The film opened in 3,472 theaters in North America and grossed $22,956,453 in its opening weekend. It grossed $134,734,481 worldwide—$95,170,481 in North America and $39,564,000 in other territories.
Review aggregator Rotten Tomatoes reported that the film had a 25% "certified rotten" rating, with an average score of 4.6/10 based on 115 critical reviews. The site's general consensus is that "Anne Hathaway and Julie Andrews bring charm and elegance to the movie, but there's not enough material for them to work with in this sequel." On Metacritic, which assigns a weighted mean rating out of 100 reviews from film critics, it has an average score of 43 from the 31 reviews, which indicates "Mixed or average reviews".
The film's writer, Shonda Rhimes, later said that she treasured the experience if for nothing else – the opportunity to work with its star, Julie Andrews.
The song, "Your Crowning Glory", a duet between Queen Clarisse (Julie Andrews) and Princess Asana (Raven-Symoné) was the first time Andrews had sung in public or on screen since she had throat surgery in 1997.
In March 2016, despite the death of producer Whitney Houston in February 2012, Garry Marshall announced that Hathaway, who was pregnant with her first child, would appear in a third Princess Diaries film after she gave birth. However, with Garry Marshall's death in July 2016, the project had been pulled. In August 2016, Hector Elizondo discussed a possibility that the third installment would still be produced. In an interview with Variety Latino, He said on the possibility, "I know Anne would like to do it. I know Julie would like to do it. I would like to do it. So we're on board, it's a question of when and a question of getting a good story. I'm ready! It's time to go back to Genovia!"