Provided are a resin composition with high adhesion to substrates under hot and humid conditions, a two-part laminate adhesive containing the resin composition, and a laminated film and backsheet for solar cells including a layer of the adhesive. The resin composition contains, as essential components, a polyester polyurethane polyol (A) having a branched structure in a molecule thereof and having a weight average molecular weight (Mw) of 25,000 to 200,000 and a molecular weight distribution (Mw/Mn) of 2.5 to 25; a hydroxyl-containing epoxy resin (B) having a number average molecular weight (Mn) of 300 to 5,000; a hydroxyl-containing polycarbonate resin (C) having a number average molecular weight (Mn) of 300 to 3,000; and a polyisocyanate (D).