We have investigated the magnetic properties of hexagonal AlSi monolayer and nanoribbons by first principles method. The armchair AlSi nanoribbons are predicted to show itinerant magnetism. Since the armchair AlSi nanoribbons can be regarded as armchair silicene nanoribbons with injected holes, the results suggest the importance of holes in inducing magnetism in armchair nanoribbons. We further discuss boron doped armchair graphene nanoribbons and predict magnetism. These results have potential applications on electronic or spintronic devices. (C) 2012 Elsevier B. V. All rights reserved.