Siemens Mobile was a mobile phone manufacturer and a division of Siemens AG. Siemens sold Siemens Mobile to the Taiwan-based BenQ in 2005, which subsequently became BenQ-Siemens. The last Siemens mobile phones, the AL21, A31 and AF51, were released in November 2005. The first Siemens mobile phone, the Siemens Mobiltelefon C1, was launched in 1985. In 1994 the Siemens S1 GSM phone was launched. In 1997 Siemens launched the first phone with a colour screen, the Siemens S10, with a screen capable of displaying red, green, blue and white. In the same year Siemens launched the first “outdoor” phone, the Siemens S10 Active, with enhanced shock, dust and splash protection.

Siemens launched the first slider phone, the Siemens SL10, in 1999.