Arn is an eleven-year-old Cambodian boy who is quick-witted, street-smart, and highly musically talented. He starts as an average kid enjoying American rock 'n' roll and movies, but is soon forced to survive the extreme brutality of Khmer Rouge labor camps. His natural charisma, adaptability, and musical skills become his primary tools for staying alive amidst escalating violence and starvation.

Mek is a former music teacher devastated by the loss of his family to the Khmer Rouge. He hates the regime's outlawing of traditional art, but eventually steps into a paternal role to protect the children in the musical ensemble from execution.

Sombo is a teenage Khmer Rouge guard who takes Arn under his wing. He acts as a dangerous but vital protector, allowing Arn small freedoms. However, his complicity in the regime's violence creates a deeply conflicted and frightening relationship between them.

Peter Pond is an American volunteer and activist working in the Thai refugee camps. Driven by deep compassion and faith, he rescues three boys from the camp and brings them to the United States, encouraging them to share their experiences with the world.

Munny is Arn’s younger brother and partner-in-crime during their peaceful days in Battambang. He represents the lost innocence of Arn's youth, sharing in playful moments before the harsh realities of the evacuation and labor camps take over their lives.

Chantou is Arn’s oldest sister, who values education and tries to maintain a sense of order in her younger brother's life. When the Khmer Rouge take over the country, the soldiers force her to surrender her college books, symbolizing the regime's hostility toward learning.

Sophea is Arn’s youngest sister. She possesses a fiery personality and physical toughness that Arn secretly respects. Her strength is severely tested when the siblings are pushed into brutal forced labor, an experience that drastically alters her physical appearance.

Hong is Arn’s childhood friend in Battambang. He comes from a wealthy Chinese family and owns his own bicycle. His family's foreign status places them in immediate danger when the new regime takes over, forcing them to flee.

Maly is Arn’s second oldest sister. She is deeply traumatized when the Khmer Rouge forcibly cut off her prized hair, an act of violence that leaves her profoundly submissive, fearful, and afraid to make eye contact with the soldiers.

Jorami is Arn’s third oldest sister. Initially holding out hope for a romantic reunion with a man from their town, her spirit slowly breaks as the unpredictable nature of the work camps causes people around her to disappear.

Kha is a skinny boy with prominent ears who plays in the propaganda band. Because he is young and vulnerable to the harsh camp conditions, he relies heavily on Arn's guidance and protection to avoid the deadly attention of the guards.

Siv is a large, somewhat clumsy boy assigned to the camp's dance troupe. He struggles with the physical demands of the performances, relying on his friends' covert interventions to avoid punishment from the guards.

Koong is a small boy forced into the combat group. He quickly becomes a favorite of the commanders due to his ability to catch rats, frogs, and insects for food during desperate times in the jungle.

Missus Carter is the First Lady of the United States. She tours the refugee facilities in Thailand, signaling to the displaced children that important international figures are paying attention to their crisis.

Missus Gotobed is the woman in charge of Arn's refugee camp. Earning her nickname from her constant commands for the children to go to bed, she nevertheless serves as the first maternal figure Arn encounters after his escape.

Runty is a small, shell-shocked former child soldier living in the Thai refugee camp. He latches onto Arn for a sense of safety, bringing out protective instincts in the older boys recovering from the war.

Sojeat is a talented, highly competitive refugee who is adopted by Peter Pond. Having received some education before the war, he adapts more quickly to American culture and academics, often clashing with Arn over their traumatic pasts.

Ravi is a tall, shy refugee boy adopted by Peter Pond. He avoids talking about the horrors of Cambodia, preferring to focus on positive aspects of his new American life, and consistently acts as a peacemaker in the household.

Kate, Doug, and Donna are Peter Pond’s biological children, who all share his distinct blue eyes. They cautiously welcome the Cambodian refugees into their home, eventually bonding over shared activities like volleyball and exchanging cultural novelties.

Shirley Pond is Peter Pond’s wife. She works hard to create a stable, disciplined home environment for the newly arrived refugees, enforcing household rules to help the boys adjust to American life despite her worries over Peter's extensive campaigning.