SJ
SJ can refer to:
- Society of Jesus (Societas Iesu) (formal name of the Jesuits, a Roman Catholic Order of men)
- Sozialistische Jugend, the youth organisation of the Social Democratic Party in countries where German is spoken
- SJ, Swedish Railways - a public transport limited company owned by the Government of Sweden
- Statens Järnvägar (SJ), or Swedish State Railways - a former Government agency in Sweden
- The ISO country code for Svalbard and Jan Mayen
- The airline code for Freedom Air, a budget airline based in New Zealand
- SJ410 or SJ413, a series of 4x4 vehicles made by Suzuki Motors
- San Jose, California