Zarząd Transportu Miejskiego w Warszawie is a local authority controlled body managing all means of public transport in Warsaw. The public transport companies running the lines governed by the ZTM are:
Miejskie Zakłady Autobusowe
Szybka Kolej Miejska
It also carries out tasks related to the implementation, management and operation of the Warsaw Public Bicycle system.
In addition to the above, ZTM contracts out some of the bus services to private companies. These include PKS Grodzisk Mazowiecki, Arriva Bus Poland, Europa Express City, Mobilis, KM Łomianki and ITS Michalczewski.