- Country: France, Italy, Spain
- Genres: Crime, Drama
- Release: 1966-05-20
- Director: Sergio Sollima
- Writers: Jesús María de Arozamena , Giovanni Simonelli , Sergio Sollima
- Language: Italian
- Stars: George Ardisson , Frank Wolff , Evi Marandi , Michel Lemoine , Fernando Sancho , Luz Márquez , Eduardo Fajardo , Leontine Snell , Claudio Ruffini , Sal Borgese
- Runtime: 106 min
- Awards: N/A
- AKA: Agente 3S3 enviado especial (Spain) , Agent 3S3, massacre au soleil (France, French Republic) , Al servicio del poder (Spain) , 3-S-3 sfagi ston ilio (Greece) , Massaker i sol (Sweden) , Agent 3S3 , Agente Especial 3S3 (Brazil) , Agent 3S3 pokert mit Moskau , Agent 3S3: Hunter from the Unknown , Agent 3S3, massacre au soleil (Canada) , 3S3, agente especial (Spain) , Agente 3S3, massacro al sole , Hunter of the Unknown (United Kingdom) , Hunter from the Unknown , Agent 3S3, Massacre in the Sun (United States of America) , Agente 3S3, massacro al sole (Italy) , Agent 3S3: Billett til helvete (Norway) , Agent 3-S-3 Paspoort naar de hel (Netherlands the)
- Plot: The island paradise of San Felipe has undergone a revolution and the charismatic General Siqueiros has assumed control. Those assisting him though have an agenda far beyond a simple dictatorship of a inconsequential banana republic.
- IMDB:tt0060075
Agent 3S3, Massacre in the Sun Cast · · · ALL
Sergio Sollima
Director
George Ardisson
Walter Ross, Agent 3S3
Frank Wolff
Ivan Mikhailovic
Evi Marandi
Melissa Shaw, British agent
Michel Lemoine
Radek
Fernando Sancho
General Emilio Siqueiros
John Karlsen
Mikhailovic's Boss
Kitty Swan
Una dell'harem di Siqueiros (as Kersten Svanhold)
Luz Márquez
Signora Barrientos
Eduardo Fajardo
Professor Theodore Karleston
Claudio Ruffini
Koko, uomo di Radek
Sal Borgese
Paco
Porfiria Sanchíz
Beni Deus
Luis Induni
Micheal Smith, Agent 3S4
Dina Loy
Ursula Rank
José Riesgo
Ennio Antonelli
Man on Plane
Romano Puppo
Man on Plane #2
Pietro Ceccarelli
Soldier
Nello Pazzafini
José, Bodyguard
Pietro Torrisi
Bodyguard #2