Svalbard and Jan Mayen (Norwegian: Svalbard og Jan Mayen, ISO 3166-1 alpha-2: SJ, ISO 3166-1 alpha-3: SJM, ISO 3166-1 numeric: 744) is a statistical designation defined by ISO 3166-1 of two parts of Norway under separate jurisdictions—Svalbard and Jan Mayen. While the two are combined for the purposes of the International Organization for Standardization (ISO) category, they are not administratively related. This has further resulted in the country code top-level domain .sj being issued for Svalbard and Jan Mayen, and ISO 3166-2:SJ. The United Nations Statistics Division also uses this code, but has named it Svalbard and Jan Mayen Islands.

Svalbard is an archipelago in the Arctic Ocean under the full sovereignty of Norway, but is subject to the special status granted by the Svalbard Treaty. Jan Mayen is a remote island in the Atlantic Ocean; it has no permanent population and is administrated by the County Governor of Nordland. Svalbard and Jan Mayen have in common that they are the only integrated parts of Norway not allocated to counties. While a separate ISO code for Svalbard was proposed by the United Nations, it was the Norwegian authorities who took initiative to include Jan Mayen in the code.