Older adults use semantic context to generate predictions in speech processing, compensating for aging-related sensory and cognitive changes. This study aimed to gauge aging-related changes in effort exertion related to context use. The study revisited data from Harel-Arbeli et al. (2023) that used a "visual-world" eye-tracking paradigm. Data on efficiency of context use (response latency and the probability to gaze at the target before hearing it) and effort exertion (pupil dilation) were extracted from a subset of 14 young adults (21 to 27 years old) and 13 older adults (65 to 79 years old). Both age groups showed a similar pattern of context benefits for response latency and target word predictions, however only the older adults group showed overall increased pupil dilation when listening to context sentences. Older adults' efficient use of spoken semantic context appears to come at a cost of increased effort exertion.