Older adults have difficulty understanding spoken language in the presence of competing voices. Everyday social situations involving multiple simultaneous talkers may become increasingly challenging in later life due to changes in the ability to focus attention. This study examined whether individual differences in cognitive function predict older adults' ability to access sentence-level meanings in competing speech using a dichotic priming paradigm. Older listeners showed faster responses to words that matched the meaning of spoken sentences presented to the left or right ear, relative to a neutral baseline. However, older adults were more vulnerable than younger adults to interference from competing speech when the competing signal was presented to the right ear. This pattern of performance was strongly correlated with a non-auditory working memory measure, suggesting that cognitive factors play a key role in semantic comprehension in competing speech in healthy aging.