This study reports 2 eye-tracking experiments investigating form interference during sentence-level silent reading. The items involved reduced and unreduced relative clauses (RCs) with words that were orthographically and phonologically similar "(injection-infection"; O+P+, Experiment 1) as well as with words that were orthographically similar, but phonologically dissimilar ("laughter-daughter"; O+P-, Experiment 2). Both experiments revealed syntactic processing disruptions for reduced RCs. Processing difficulty was also observed at the form-related word in both experiments under first-pass and second-pass reading measures. These form-interference effects did not interact with structural processing difficulty under first-pass measures in either experiment. Under second-pass time, there were larger processing disruptions for reduced RCs in O+P+ sentences relative to their controls. This was not the case, however, for O+P- sentences. These results suggest 2 components to form-interference effects during silent reading: (a) an early, low-level component that is driven in large part by visual form overlap and (b) a component that relates to late stages of interpretation and that is associated more closely with phonological form overlap.