To understand language, we use knowledge about everyday events to create rich internal (situation) models. Although knowledge increases with age, fluid cognitive abilities tend to decline, potentially making it more difficult to access that knowledge. Here, we asked how aging affects the ability to use event knowledge during real-time language comprehension. We recorded event-related brain potentials as younger and older adults read vignettes about everyday events. Both groups showed facilitation on the N400 (a neuroelectric marker of semantic processing) for words that fit the context. However, only younger adults showed facilitated N400s to anomalous but event-related words compared to unrelated anomalies. Among older adults (aged 53-80), there was a negative correlation between age and N400 effects of event-relatedness. We conclude that real-time access to event knowledge during language comprehension may shift across the course of the adult lifespan such that older adults restrict activation to the most immediately relevant content.