The IUPAC nomenclature of organic chemistry is a method of naming organic chemical compounds as recommended by the International Union of Pure and Applied Chemistry (IUPAC) . It is a system of rules and guidelines used to give unambiguous and absolute definitions to organic compounds. The IUPAC system is based on naming a molecules longest chain of carbons connected by single bonds, whether in a continuous chain or in a ring. All deviations, either multiple bonds or atoms other than carbon and hydrogen, are indicated by prefixes or suffixes according to a specific set of priorities.

The IUPAC naming system can sometimes be simpler than older names, as with ethanol, instead of ethyl alcohol. For relatively simple molecules, they can be more easily understood than non-systematic names, which must be learned or looked over. However, to avoid long and tedious names in normal communication, the official IUPAC naming recommendations are not always followed in practice, except when it is necessary to give an unambiguous and absolute definition to a compound.

In order to name organic compounds using the IUPAC rules, one must first memorize a few basic names. The IUPAC system is used worldwide and is known as the IUPAC System of Nomenclature. Simplified IUPAC rules for naming alkanes are as follows: name alkanes according to the longest chain of carbon atoms in the molecule (rather than the total number of carbon atoms). This longest chain, considered the parent chain, determines the base name, to which we add the suffix -ane to indicate that the molecule is an alkane/11%3A_Organic_Chemistry/11.06%3A_IUPAC_Nomenclature).

IUPAC is the universally-recognized authority on chemical nomenclature and terminology, and it develops recommendations to establish unambiguous, uniform, and consistent nomenclature and terminology for specific scientific fields, usually presented as glossaries of terms for specific chemical disciplines, definitions of terms relating to a group of properties, nomenclature of chemical compounds and their classes, terminology, symbols, and units in a specific field, classifications and uses of terms in a specific field, and conventions and standards of practice for presenting data in a specific field.