A vast number of ancient Roman deities are known by name. The most familiar today are those the Romans identified with Greek counterparts, integrating Greek myths, iconography, and sometimes religious practices into Roman culture, including Latin literature, Roman art, and religious life as it was experienced throughout the Empire. Many of the Romans' own gods remain obscure, known only by name and function, through inscriptions and texts that are often fragmentary—particularly those who belong to the archaic religion of the Romans dating back to the era of kings, the so-called "religion of Numa," perpetuated or revived over the centuries. Some archaic deities have Italic or Etruscan counterparts, as identified both by ancient sources and by modern scholars. Throughout the Empire, the deities of peoples in the provinces were given new theological interpretations in light of functions or attributes they shared with Roman deities.

An extensive alphabetical list follows a survey of theological groups as constructed by the Romans themselves. For cult pertaining to deified Roman emperors (divi), see Imperial cult.

The Greek is a fictional character on the HBO drama The Wire, played by actor Bill Raymond. The Greek is the head of an international criminal organization involved in narcotics and human trafficking. The Greek is a mysterious figure involved in numerous criminal activities. His given name is never mentioned on the show, and though he is known only as "The Greek", he has stated (in the episode Port in a Storm) that he is not actually Greek. A quiet and unassuming man, the Greek prefers to keep a low profile, operating all of his business through his lieutenant Spiros "Vondas" Vondopoulos. His smuggling organization operated from a small diner in Baltimore for years, and while Vondas would conduct business the Greek would listen in quietly at the counter. Nick Sobotka, upon seeing the Greek identify himself, was amazed that the shadowy figure had been in plain sight the entire time.

Despite his calm appearance, the Greek is cunning and ruthless, and only interested in facts that make him more money. Series creator David Simon has said that The Greek is an embodiment of raw unencumbered capitalism. Anyone interfering in this process is eliminated immediately, and he prefers to leave victims headless and handless to hinder identification.