Although younger and older adults can use context effectively to understand spoken language, at times the context may fit multiple semantic competitors, and choosing the correct one can be crucial for comprehension. Given the ambiguities present in the real world, and the inhibitory control deficit common in aging, it is critical to understand how adults of all ages comprehend sentences. An experiment is reported to explore the interplay of context and competition in sentence comprehension using a variation on a visual world eye-tracking paradigm. Spoken sentences were presented with either high or low expectancy (context) for a sentence-final (target) word and with either high or low response entropy (uncertainty or competition); these target words were then paired with either a contextual competitor or an unrelated lure. Results support the expectation that lower context and greater competition slow comprehension and increase cognitive effort. Results will be discussed in terms of aging and individual differences. [Work supported by NIH Grants RO1 AG 019714 and T32 GM 084907.]