Gibbs' rules are a set of rules developed by Leroy Jethro Gibbs, a character on the show "NCIS." He got the idea from his first wife and began writing down his rules. He follows his rules and teaches them to people on his team.
Gibbs' rules are mentioned throughout the series. Examples of the rules include, "Never let suspects sit together" and "Never believe what you are told. Double check." After writing down a rule, he keeps it in a tin. Although he attempts to follow every rule, he has broken certain rules.
His list of rules has certain numbers duplicated, so there are two separate rules listed as rule one. Rules 40 through 49 are rules for emergencies.