This study examined how different verbal distractors influence (age-related) performance in the operation span working memory task. Forty-six older (M = 68 years, SD = 3.82) and 49 younger adults (M = 27 years, SD = 3.02) performed a conventional operation span task version and three versions with non-related, conceptually related, or phonologically related distracting words. Thus, the amount of inhibitory control demands varied across the task versions. Age effects were found for all versions. Furthermore, age effects in the versions with distracting words were even larger than in the conventional version, indicating that a decline in the ability to inhibit irrelevant verbal information can partly explain age effects in working memory performance.