The Princess Diaries 2: Royal Engagement is the 2004 sequel to 2001's The Princess Diaries.

Anne Hathaway, Julie Andrews, Hector Elizondo, and Heather Matarazzo return to portray their characters from the first Princess Diaries film, Princess Mia Thermopolis, Queen Clarisse Renaldi, Joe (Mia's bodyguard/chauffer) and Lilly Moscovitz accordingly. Garry Marshall returned to direct and Debra Martin Chase to produce the sequel.

New characters include Viscount Mabrey, played by John Rhys-Davies, the evil nobleman who tries steal the throne from the House of Renaldi. The viscount's nephew, Lord Nicholas Devereaux, who eventually turns against his uncle is played by Chris Pine, who previously had never appeared in a film. Andrew Jacoby, the man whom Mia is supposed to marry, is played by Callum Blue.

In the film, Mia Thermopolis journeys to Genovia for vacation after graduating from college before taking up her job as princess of Genovia. She continues her royalty lessons and prepares herself to take up the throne as queen of Genovia. However, the Viscount Mabrey, who wants his nephew to rule as king, brings up a little known--and rarely enforced--law that a princess must marry before taking the throne. The Genovian Parliament gives Mia thirty days to marry.

Mia, with her romantic fantasies of true love, is aghast to discover the only way to prevent Genovia from falling into Lord Nicholas Devereaux's (Mabrey's nephew) hands is an arranged marriage. After seeing a list of choices, Mia chooses Andrew Jacoby, the Duke of Kenilworth. Mabrey is furious and decides to have his nephew to romance Mia, so she falls in love with him and doesn't marry Andrew. However, Nicholas starts to have second thoughts about his uncle's deceitful plans. He and Mia fall in love, but Mia still chooses to marry Andrew because she believes it is her duty to her country.

Nicholas travels to the wedding on an old-fashioned bicycle in order to stop his uncle from seizing the throne. Mia changes her mind about marrying Andrew at the last minute and presents a speech broadcasted throughout Genovia as to her reasons for not marrying and requests that they accept her as queen. Mabrey takes advantage of the fact Mia has been highly unorthodox and claims she has no respect for Genovian laws and traditions. Nicholas arrives and denounces his uncle's claims and acknowledges Mia's right to the throne. Mia asks Parliament to change the law and, to Mabrey's chagrin, they agree.

Rather than letting all the wedding preparation go to waste, Queen Clarisse and Joe, who have been having a sort-of romance since the death Clarisse's husband, decide to marry. This is often seen as an example of fan service, since the pairing of Clarisse and Joe was extremely popular among fans of the first film.

On the morning of Mia's coronation, she questions if she would be a capable ruler. Nicholas appears before her to reassure her. He admits his feelings for her and inquires if she feels the same. The story ends with Mia's coronation as Queen of Genovia and scenes of a slowly changing Genovia under her rule.