Robert Arden (11 December 1922 – 25 March 2004) was an American film, television and radio actor born in London who worked and lived mostly in the United Kingdom.

Arden was born from an American father and an English mother. His father had a successful career as a professional boxer after World War I. He attended "a combination of English and American schools."

Arden's most famous film appearance was as lead character Guy Van Stratten in Mr. Arkadin (1955), written and directed by Orson Welles. Welles had worked with Arden on the Harry Lime radio series, produced in London, and later cast the little-known actor in Mr. Arkadin, in the central role of the investigator who uncovers Arkadin's past. Reportedly, Arden was shocked that Welles might consider him for the part and initially thought that the director's phone inquiry was a crank call.

Arden's performance in Mr. Arkadin was panned by some critics : The New York Times called it "hopelessly inadequate". Film historian Jonathan Rosenbaum has defended Arden's performance, locating the problem not in the actor's work but in "the unsavoriness and obnoxiousness of the character", who was intended by Welles to be unattractive even though he occupied in the film "the space normally reserved for charismatic heroes".

The credits of one the film's Spanish versions misspelled Arden's name as "Bob Harden". Another Spanish print actually credited him as "Mark Sharpe".

Mr. Arkadin did poorly at the box-office. Afterwards, Arden played a few other lead roles, in films such as The Depraved (1957) or The Child and the Killer (1959), but he worked mostly as a character actor, appearing in film, television and stage productions. he worked mostly as a character actor, appearing in film, television and stage productions.