Storstockholms Lokaltrafik (SL), or more formally Aktiebolaget Storstockholms Lokaltrafik, is the organisation running all of the land based public transport systems in Stockholm County. It was previously known as Stockholms Lokaltrafik.

Transport in Stockholm consists of roads, buses, metro, commuter rail, Inter-city rail, regional rail, light rail, tram, commuter ferry and an archipelago boat operation in Stockholm County, Sweden. The bus and rail is organized by Storstockholms Lokaltrafik, SL, which is owned by the Stockholm County Council. Tickets for all SL services can be purchased most easily in the SL app. For single tickets, just tap a credit card against the turnstiles and on buses. A single ticket is valid for 75 minutes, costs 39 SEK in 2023. The operation and maintenance of the public transport systems are delegated by SL to several contractors. The archipelago boat traffic is handled by Waxholmsbolaget.