Magnetism of armchair graphene nanoribbons attached with O, CH(2), or NH radical groups are investigated within the framework of density functional theory. A variety of interesting band structures of semi-metals, spin gapless semiconductors, and semiconductors are obtained. Among the three radical groups considered, CH(2) can induce the strongest magnetism with 2 mu(B) magnetic moment per group. The magnetism is found to come from the unsaturated states on the C atoms at the edges and in the radical groups. No spin polarization is triggered in the ribbons with NH radicals. Our study provides a possible way to carry out d(0) magnetism in armchair graphene nanoribbons. (C) 2011 Elsevier B.V. All rights reserved.