Purpose: The present study tested whether (and how) language treatment changed online sentence processing in individuals with aphasia. Method: Participants with aphasia (n = 10) received a 12-week program of Treatment of Underlying Forms (Thompson & Shapiro, 2005) focused on production and comprehension of passive sentences. Before and after treatment, participants performed a sentence-picture matching task with active and passive sentences as eye movements were tracked. Twelve age-matched controls also performed the task once each. Results: In the age-matched group, eye movements indicated agent-first predictive processing after hearing the subject noun, followed by rapid thematic reanalysis after hearing the verb form. Pretreatment eye movements in the participants with aphasia showed no predictive agent-first processing, and more accurate thematic analysis in active compared to passive sentences. After treatment, which resulted in improved offline passive sentence production and comprehension, participants were more likely to respond correctly when they made agent-first eye movements early in the sentence, showed equally reliable thematic analysis in active and passive sentences, and were less likely to use a spatially based alternative response strategy. Conclusions: These findings suggest that treatment focused on improving sentence production and comprehension supports the emergence of more normal-like sentence comprehension processes.