We examined native and non-native English speakers' processing of indirect object "wh"-dependencies using a filled-gap paradigm while recording event-related potentials (ERPs). The non-native group was comprised of native German-speaking, proficient non-native speakers of English. Both participant groups showed evidence of linking fronted indirect objects to the subcategorizing verb when this was encountered, reflected in an N400 component. Evidence for continued filler activation beyond the verb was seen only in the non-native group, in the shape of a prolonged left-anterior negativity. Both participant groups showed sensitivity to filled indirect object gaps reflected in a P600 response, which was more pronounced and more globally distributed in our non-native group. Taken together, our results indicate that resolving indirect object dependencies is a two-step process in both native and non-native sentence comprehension, with greater processing cost incurred in non-native compared to native comprehension.