Named after Alser Straße, the road named after the Als stream.
The street was named in 1862 after the Als, a stream from the Wienerwald that was walled in during the 19th century and now flows underground. The road itself is far older: it appears in 1211 as ‘vicus Alsaerstrâzze’. The stream's name originally meant ‘the moist one’; the old idea of a Celtic origin is considered mistaken.