We investigate the Higgs boson production through gluon fusion and its decay into two photons at the LHC in the context of the minimal 3-3-1 model and its alternative version with exotic leptons. The diphoton Higgs decay channel presents an enhanced signal in this model compared to the standard model due to the presence of an extra singly charged vector boson and a doubly charged one. Prospects for the Higgs boson detection at 7TeV center-of-mass energy with up to 10fb -1 are presented. Our results suggest that a Higgs boson from these 3-3-1 models can potentially explain the small excess for m H≤145GeV observed at the LHC. Otherwise, if this excess reveals to be only a statistical fluctuation of the standard model backgrounds, severe constraints can be put on these models. © 2011 American Physical Society.