ISO 3166-1 numeric (or numeric-3) codes are three-digit country codes defined in ISO 3166-1, part of the ISO 3166 standard published by the International Organization for Standardization (ISO), to represent countries, dependent territories, and special areas of geographical interest. They are similar to the three-digit country codes developed and maintained by the United Nations Statistics Division, from which they originate in its UN M.49 standard. They were first included as part of the ISO 3166 standard in its second edition in 1981, but they were released by the United Nations Statistics Division since as early as 1970.

An advantage of numeric codes over alphabetic codes is script (writing system) independence. The ISO 3166-1 alphabetic codes (alpha-2 and alpha-3) use letters from the 26-letter English alphabet and are suitable for languages based on the Latin alphabet. For people and systems using non-Latin scripts (such as Arabic or Japanese), the English alphabet may be unavailable or difficult to use, understand, or correctly interpret. While numeric codes overcome the problems of script dependence, this independence comes at the cost of loss of mnemonic convenience.

Another advantage is that when countries merge or split, they will get a new numeric code, while the alphabetic code stays in use for (a part of) that country. A persistent number is needed in datasets with historical country information.