Voltage-gated sodium channels are essential for initiating and propagating action potentials in excitable cells. These channels consist of a major α subunit (~260 kDa) and auxiliary β subunits. The functional properties of sodium channels are relatively similar, but they have been named in many different ways, leading to confusion. To resolve this, a standardized nomenclature is proposed, based on that of voltage-gated potassium channels. The name of a sodium channel is denoted as NaV followed by a number indicating the subfamily and a decimal point followed by a number indicating the isoform (e.g., NaV1.1). Splice variants are denoted by lowercase letters (e.g., NaV1.1a). Nine mammalian sodium channel isoforms have been identified and functionally expressed. These isoforms are greater than 50% identical in amino acid sequence in the transmembrane and extracellular domains. Phylogenetic analysis shows that these channels form a single family, with NaV1.1, NaV1.2, NaV1.3, and NaV1.7 being the most closely related. Other isoforms, such as NaV1.5, NaV1.8, and NaV1.9, are also closely related and share high sequence similarity. NaV1.4 and NaV1.6 are more distantly related and are expressed in skeletal muscle and the CNS, respectively. Closely related sodium channel-like proteins have been cloned but not yet functionally expressed. These proteins are more than 80% identical to each other but show significant differences in voltage sensors, inactivation gates, and pore regions. They are expressed in various tissues and may not be highly sodium selective or voltage gated. These proteins are closely related to the sodium channels on human chromosome 2q23–24. Three auxiliary subunits (β1, β2, β3) have been defined. Additional subunits should be named β4 to βn if identified. The family of voltage-gated sodium channels is expanding, with distinct tissue distributions and potential physiological functions. The proposed nomenclature aims to provide a common standard for communication and comparison. This nomenclature has been reviewed and accepted by the Nomenclature Committee of the International Union of Pharmacology.Voltage-gated sodium channels are essential for initiating and propagating action potentials in excitable cells. These channels consist of a major α subunit (~260 kDa) and auxiliary β subunits. The functional properties of sodium channels are relatively similar, but they have been named in many different ways, leading to confusion. To resolve this, a standardized nomenclature is proposed, based on that of voltage-gated potassium channels. The name of a sodium channel is denoted as NaV followed by a number indicating the subfamily and a decimal point followed by a number indicating the isoform (e.g., NaV1.1). Splice variants are denoted by lowercase letters (e.g., NaV1.1a). Nine mammalian sodium channel isoforms have been identified and functionally expressed. These isoforms are greater than 50% identical in amino acid sequence in the transmembrane and extracellular domains. Phylogenetic analysis shows that these channels form a single family, with NaV1.1, NaV1.2, NaV1.3, and NaV1.7 being the most closely related. Other isoforms, such as NaV1.5, NaV1.8, and NaV1.9, are also closely related and share high sequence similarity. NaV1.4 and NaV1.6 are more distantly related and are expressed in skeletal muscle and the CNS, respectively. Closely related sodium channel-like proteins have been cloned but not yet functionally expressed. These proteins are more than 80% identical to each other but show significant differences in voltage sensors, inactivation gates, and pore regions. They are expressed in various tissues and may not be highly sodium selective or voltage gated. These proteins are closely related to the sodium channels on human chromosome 2q23–24. Three auxiliary subunits (β1, β2, β3) have been defined. Additional subunits should be named β4 to βn if identified. The family of voltage-gated sodium channels is expanding, with distinct tissue distributions and potential physiological functions. The proposed nomenclature aims to provide a common standard for communication and comparison. This nomenclature has been reviewed and accepted by the Nomenclature Committee of the International Union of Pharmacology.