Diplomats — reference index 9
- Leif Leifland — Sweden
- Leighton McCarthy — Canada
- Leopoldo Augusto de Cueto — Spain
- Lester B. Pearson — Canada
- Lew Byong-hion — Korea
- Lewis Cass
- Li Daoyu — China
- Li Kexin — China
- Li Zhaoxing — China
- Liang Cheng — China
- Lianys Torres Rivera — Cuba
- Lin Zhaonan — China
- Lord Halifax — United Kingdom
- Lord Inverchapel — United Kingdom
- Lord Lyons — United Kingdom
- Lord Napier — United Kingdom
- Loring Christie — Canada
- Louis de Geofroy — France
- Louis McLane
- Louis-André Pichon — France
- Louis-Charles-Barbé Sérurier — France
- Louis-Guillaume Otto — France
- Louis-Marie Turreau — France
- Lucien-Anatole Prévost-Paradol — France
- Lucio García del Solar — Argentina
- Ludwig Niederstetter — Germany
- Ludwig von Arco-Valley — Germany
- Lui Tuck Yew — Singapore
- Luigi Avogadro di Collobiano Arborio — Italy
- Luigi Corti — Italy
- Luigi Gerolamo Cusani Confalonieri — Italy
- Luis Calderón y Martín — Spain
- Luis de la Rosa Oteiza — Mexico
- Luis de Onís — Spain
- Luis de Potestad — Spain
- Luis Lorenzo Domínguez — Argentina
- Luis Machado — Cuba
- Luis Marchand Stens — Peru
- Luis Miguel Castilla — Peru
- Luis Pastor — Spain
- Luis Polo de Bernabé y Pilón — Spain
- Luis S. Luti — Argentina
- Luis Valdivieso Montano — Peru
- Luiz Alberto Figueiredo — Brazil
- Luiz Augusto de Pádua Fleury — Brazil
- Luiz Pereira Sodré — Brazil
- Lukman Faily — Iraq
- Lyndon B. Johnson
- M. C. Chagla — India
- M. K. Kirpalani — India
- M. Rasgotra — India
- Madeleine Albright
- Magzhan Ilyassov — Kazakhstan
- Mahendra Siregar — Indonesia
- Mahmoud Hassan Pasha — Egypt
- Mahmoud Samy Pasha — Egypt
- Mahmud Ali Durrani — Pakistan
- Maleeha Lodhi — Pakistan
- Manlio Brosio — Italy
- Manuel Allendesalazar y Azpiroz, Count of Montefuerte — Spain
- Manuel Azpíroz — Mexico
- Manuel Álvarez Calderón — Peru
- Manuel C. Téllez — Mexico
- Manuel Calero y Sierra — Mexico
- Manuel de Freyre y Santander — Peru
- Manuel de Oliveira Lima — Brazil
- Manuel Eduardo de Gorostiza — Mexico
- Manuel Freyre y Santa Cruz — Peru
- Manuel Larráinzar — Mexico
- Manuel Malbrán — Argentina
- Manuel María de Zamacona e Inclán — Mexico
- Manuel María de Zamacona y Morfi — Mexico
- Manuel Márquez Sterling — Cuba
- Manuel Pérez Romero — Mexico
- Manuel Rafael García Aguirre — Argentina
- Manuel Robles Pezuela — Mexico
- Manuel Tello Baurraud — Mexico
- Manuel Walls y Merino — Spain
- Manuel Y. de Negri — Mexico
- Mao Zedong
- Marcel Cadieux — Canada
- Marcello Cerruti — Italy
- Marcello Serafini — Italy
- Marcílio Marques Moreira — Brazil
- Marco Peronaci — Italy
- Marco Rubio
- Marcos Antônio de Araújo e Abreu — Brazil
- Maria Luiza Ribeiro Viotti — Brazil
- Maria Stela Pompeu Brasil Frota — Brazil
- Mariangela Zappia — Italy
- Mariano Amoedo y Galarmendi — Spain
- Mariano Yturralde y Orbegoso — Spain
- Mark D. Wiseman — Canada
- Marquis Imperiali — Italy
- Martha Elena Federica Bárcena Coqui — Mexico
- Martin Van Buren
- Martín García Mérou — Argentina
- Martín Lousteau — Argentina
- Martín Luis Drago — Argentina
- Mary Foote Henderson