On the 30th anniversary of his wedding with Lisa McDowell, Prince Akeem of Zamunda is now summoned before his dying father King Jaffe Joffer. Jaffe and his witch doctor Baba reveal to Akeem that he had sired a bastard son during his first visit to Queens, New York, many years ago, after his aide and long-time best friend Semmi had enticed two women into spending the night with them while Akeem was still searching for his future queen, and resulting in a tryst with one he didn’t remember. As Zamundian tradition demands that only a male successor can inherit the throne and Akeem has fathered only daughters, he is forced to find his son. Otherwise, Zamunda could face a hostile takeover by Zamunda’s militaristic neighbor nation Nexdoria, whose dictator General Izzi has been pushing for Akeem’s eldest daughter Meeka to marry his foppish son Idi.

Following King Jaffe’s funeral and Akeem’s ascension to the throne, he and Semmi return to Queens to find his illegitimate long-lost son, using a sketch Baba has provided. Reuniting with the barbershop gang they befriended many years earlier in their neighborhood that went through gentrification, head barber Mr. Clarence recognizes the picture as Lavelle Junson, a ticket scalper who hustles outside of Madison Square Garden. After an awkward reunion with Lavelle’s mother Mary, Akeem takes them back to Zamunda, much to his family’s displeasure. When General Izzi learns of this, he introduces his daughter Bopoto to Lavelle as a last attempt at laying claim to the throne of Zamunda. In order to qualify as a royal prince, Lavelle first has to pass a series of traditional tests.

Lavelle bonds with Mirembe, a royal groomer who tells him of Akeem’s quest to find his queen and encourages him to follow his own path. Lavelle then invites his maternal uncle Reem to Zamunda who coaches him on how to blend his urban upbringing with his new royal status. Lavelle gradually develops an understanding with Akeem’s family, passes the tests, and is made Prince of Zamunda. However at his ascension party, Lavelle overhears a conversation between Akeem and Izzi which makes him believe that Akeem is exploiting him, and he, Mirembe, Mary, and Reem go back to New York. Lisa confronts Akeem about his conservatism and after a pep talk from his father-in-law Cleo, Akeem flies back to the States while Semmi is left to defend the kingdom from Izzi’s army.

In Queens, Akeem finds that Lavelle and Mirembe are about to get married. Confronted by Lavelle and reminded of his own life story, he gives them his blessing and releases Lavelle from his marriage to Bopoto. When Mirembe expresses reluctance in cutting all of their ties to Zamunda, Akeem offers to fly Mary’s family back for a proper wedding. In the meantime, Semmi and the princesses, all trained staff fighters, fight off and subdue Izzi and his soldiers when they invade the palace, forcing Izzi to try a more diplomatic approach.

Upon his return home, Akeem changes the royal succession by allowing his daughter Meeka to ascend to the throne upon his death, Lavelle is made an ambassador to the United States, and General Izzi has opened Nexdoria for a peaceful political and trading relationship with Zamunda.

The film concludes with a grand party at the royal palace to celebrate Lavelle and Mirembe’s marriage, and including the barbershop gang from Queens as special guests and a performance of the song “We Are Family” from Sexual Chocolate where Reem and Randy Watson are cousins. The entire family then takes a group photo.