Ambrose C. Park, left on a park bench as an infant with an impulsive need to find his parents, is an assistant to a diamond cutter. Shyster lawyer Remlick, in a strategy to get a fabulous uncut diamond through Ambrose, arranges for Emily Drummon, Duke Fargoh and Maggie Drummon to pose as Ambrose's long-lost parents and sister. The diamond, through many comic situations, is acquired and the gang is going to have Ambrose cut the diamond, and relieve him of the two stones and his parental illusions at the same time. But Maggie, who has no taste for the deception, tips Ambrose off and a wild chase ensues. At the end, Ambrose is very happy as he can now marry his "sister."
Is The Great Diamond Robbery on Netflix? Unfortunately the movie The Great Diamond Robbery is not yet available on Netflix.
| Writing | László Vadnay | Screenplay |
| Directing | Robert Z. Leonard | Director |
| Writing | Martin Rackin | Screenplay |
| Writing | László Vadnay | Story |
| Camera | Joseph Ruttenberg | Director of Photography |
| Sound | Douglas Shearer | Recording Supervision |
| Art | Edwin B. Willis | Set Decoration |
| Directing | Joe Nayfack | Assistant Director |
| Art | Cedric Gibbons | Art Direction |
| Editing | George White | Editor |
| Costume & Make-Up | William Tuttle | Makeup Artist |
| Directing | Dolph Zimmer | Assistant Director |
| Art | Jack D. Moore | Set Decoration |
| Sound | Norwood A. Fenton | Sound |
| Production | Edwin H. Knopf | Producer |
| Art | Daniel B. Cathcart | Art Direction |
| Sound | Rudolph G. Kopp | Music Director |
| Costume & Make-Up | Sydney Guilaroff | Hairstylist |
| Production | Charles J. Hunt | Unit Manager |
