| Quarta Flottiglia MAS | |
|---|---|
 Italian midget submarine with naval personnel in a Crimean port | |
| Active | May 1942–20 May 1943 |
| Country |  Italy |
| Branch | Regia Marina |
| Type | MAS flotilla |
| Role | Anti-submarine warfare Raiding Torpedo warfare |
| Garrison/HQ | Yalta |
| Nickname(s) | IVª Flottiglia MAS 101ª Squadra 101ª Flottiglia MAS |
| Equipment | MAS boats CB-class midget submarines MTSM attack crafts MTM "Barchini" motor assault boats |
| Engagements | Sinking of the Soviet submarine Shch-214, Sinking of the Soviet heavy cruiser Molotov, Sinking of the Soviet submarine Shch-203 |
| Commanders | |
| Notable commanders | Francesco Mimbelli |
The Quarta Flottiglia MAS (Quarta Flottiglia Motoscafi Armati Siluranti) (Italian for "4th Assault Vehicle Flotilla") was an Italian flotilla of the Regia Marina (Italian Royal Navy) created during the Fascist regime.