The present invention provides waterborne curable film-forming compositions comprising: a) an aqueous dispersion of polymeric acrylic particles, wherein the particles have a Z average particle size less than 80 nm and have reactive functional groups; wherein the particles are prepared from a monomer mixture comprising ethylenically unsaturated monomers that are polymerized in the presence of a branched polymer having an acid value of 40-200, wherein the branched polymer is prepared from ethylenically unsaturated monomers; b) a crosslinking agent having functional groups reactive with functional groups on the polymeric acrylic particles; and c) an aqueous dispersion of at least one additional polymer having hydroxyl and/or acid functional groups and having a Z average particle size greater than 100 nm. Further provided are multilayer coated substrates comprising the curable film-forming compositions and methods for forming a composite coating on a substrate using the curable film-forming compositions.