  The performance of the three-level ATLAS muon trigger as evaluated by using
LHC data is presented. Events have been selected by using only the
hardware-based Level-1 trigger in order to commission and to subsequently
enable the (software-based) selections of the High Level Trigger. Studies
aiming at selecting prompt muons from J/{\psi} and at reducing non prompt muon
contamination have been performed. A brief overview on how the muon triggers
evolve with increasing luminosity is given.

Instrumentation and Detectors;High Energy Physics - Experiment