- Kaing Guak Eav, alias Duch: Ran the S-21 prison known as Toul Sleng.
- Nuon Chea: Also known as “Brother Number 2.” Served as deputy secretary of the Communist Party of Cambodia.
- Khieu Samphan: The Khmer Rouge regime’s titular head of state and foreign minister.
- Ieng Sary: Served as the Khmer Rouge minister of foreign affairs. Died in 2013, before the trial concluded.
- Ieng Thirith: Served as the minister of social affairs in the Khmer Rouge regime. She has been deemed mentally unfit to stand trial.
- Meas Muth: Former Secretary Division 164 of the Revolutionary Army of Kampuchea and Commander of the Navy in Cambodia from April 1975 to January 1979.
- Im Chaem: Served as the Secretary of Preah Net Preah District in the North-West Zone.
- Ao An
- Yim Tith
- Chea Leang, National Co-Prosecutor
- Nicholas Koumjian, International Co-Prosecutor
For Kaing Guak Eav, Case 001
- Kar Savuth
- Francois Roux (Discharged by Duch in 2010)
- Kang Ritheary
For Nuon Chea, Case 002
- Son Arun
- Victor Koppe
For Khieu Samphan, Case 002
- Kong Sam Onn
- Anta Guissé
For Meas Muth, Case 003
- Ang Udom
- Michael Karnavas
For Im Chaem, Case oo4/01
- Bit Seanglim
- Wayne Jordash, QC
For Ao An, Case 004
- Mom Luch
- Richard Rogers
- Göran Sluiter
For Yim Tith, Case 004
- So Mosseny
- Suzana Tomanovic
- You Bunleng, National Co-Investigating Judge
- Michael Bohlander, International Co-Investigating Judge
Trial Chamber Judges
- Nil Nonn, National Judge (President)
- Claudia Fenz, International Judge
- Ya Sokhan, National Judge
- Jean-Marc Lavergne, International Judge
- You Ottara, National Judge
Pre-Trial Chamber Judges
- Prak Kimsan, National Judge (President)
- Olivier Beauvallet, International Judge
- Ney Thol, National Judge
- Baik Kang Jin, International Judge
- Huot Vuthy, National Judge
Supreme Court Chamber Judges
- Kong Srim, National Judge (President)
- Agnieszka Klonowiecka-Milart, International Judge
- Som Sereyvuth, National Judge
- Chandra Nihal Jayasinghe, International Judge
- Mong Monichariya, National Judge
- Florence Ndepele Mwachande Mumba, International Judge
- Ya Narin, National Judge
Key groups, Organizations and Individuals
- The Documentation Center of Cambodia (DC-Cam): An independent Cambodian research institute dedicated to documenting and preserving information about the Khmer Rouge regime.
- Tony Kranh: Acting Director of the Office of Administration. The office of administration handles the relations with the courts’ donors.
- Knut Rosandhaug: Deputy Director of the Office of Administration and Coordinator for United Nations Assistance to the Khmer Rouge Trials.
- Pol Pot: The leader of the Khmer Rouge. Died in 1998 before the tribunal proceedings began.
- Ambassador David Scheffer: U.N. Secretary-General’s Special Expert on United Nations Assistance to the Khmer Rouge Trials.