In one prominent theoretical account of second language processing, the Shallow Structure Hypothesis (Clahsen & Felser, 2006) proposes that L2 processing is qualitatively different from L1 processing, particularly with regard to online sensitivity to abstract morphosyntactic detail and to the representation of distance dependency. The present study examined whether these predictions hold for the non-native processing of Spanish case markers, which are an abstract but critical component of sentence comprehension because the language has flexible word order.