A glass fiber-reinforced polyolefin resin material, containing: a glass fiber; and a thermoplastic resin, wherein said thermoplastic resin contains: at least, a specific graft-modified polypropylene, wherein, with respect to the graft-modified polypropylene, each specific amounts of the glass fiber and a compound or polymer having an acid anhydride structure are contained, and wherein, in the content of a graft-modification component in the graft-modified polypropylene, the content of a component obtained from the (meth)acrylate containing an epoxy group is 0.5 or more and 10 or less parts by mass with respect to 100 parts by mass of said polypropylene, and a component obtained from the aromatic vinyl compound has a mass equal to or less than said component obtained from the (meth)acrylate; a composition for said resin material; a method of producing the same; and a composite.