Context : Determining the metal content of low-mass members of young associations provides a tool that addresses different issues , such as triggered star formation or the link between the metal-rich nature of planet-host stars and the early phases of planet formation .
The Orion complex is a well known example of possible triggered star formation and is known to host a rich variety of proto-planetary disks around its low-mass stars .
Available metallicity measurements yield discrepant results .

Aims : We analyzed FLAMES/UVES and Giraffe spectra of low-mass members of three groups/clusters belonging to the Orion association .
Our goal is the homogeneous determination of the metallicity of the sample stars , which allows us to look for [ Fe/H ] differences between the three regions and for the possible presence of metal-rich stars .

Methods : Nine members of the ONC and one star each in the \lambda Ori cluster and OB1b subgroup were analyzed .
After the veiling determination , we retrieved the metallicity by means of equivalent widths and/or spectral synthesis using MOOG .

Results : We obtain an average metallicity for the ONC [ Fe/H ] ~ { } = -0.01 \pm 0.04 .
No metal-rich stars were detected and the dispersion within our sample is consistent with measurement uncertainties .
The metallicity of the \lambda Ori member is also solar , while the OB1b star has an [ Fe/H ] significantly below the ONC average .
If confirmed by additional [ Fe/H ] determinations in the OB1b subgroup , this result would support the triggered star formation and the self-enrichment scenario for the Orion complex .

Conclusions :