According to Reborn, Omerta is the "Vow of Silence." It is a Mafia code that prevents members of Mafia Famiglias from talking to authorities, rival Famiglia Members, or anyone outside of their Famiglia about their own Famiglia's business. Omerta is a key plot device during the Kokuyo Arc when Futa is kidnapped by the Kokuyo Gang. It prevented him from revealing the inner secrets of the Vongola to Mukuro Rokudo and ultimately affected his ability to make rankings.
- Rings protected by Omerta can emit Dying Will Flames.
- A mafioso must be killed in order to protect Omerta.
- This vow is based on the real-life mafia form of Omertà. The common definition of omertà is the "code of silence."