Background. Age-related changes to motor speech performance are only partially explained by physiological changes in the speech system. This systematic review gathered evidence on the potential role of cognitive abilities.Method. The protocol was pre-registered on PROSPERO (CRD42021235159). PsychInfo, PubMED, Web of Science, and the Cochrane Library were last searched on 05/08/2021. Eligible studies measured relationships between cognitive and motor speech abilities in healthy adults, and/or those with mild cognitive impairment (MCI), aged 60+ years. Data were extracted, and study quality was evaluated using the Mixed Methods Appraisal Tool (MMAT; Hong et al., 2018). Results were tabulated and presented using a narrative synthesis.Results. Thirty-two studies including 1,990 older adults were identified. Ten of 23 studies investigating attention/executive functioning reported significant relationships with speech in 611 healthy older adults. In MCI, the strongest evidence is for a relationship between long-term memory and pausing, identified in 4 of 4 studies of 148 participants. For other cognitive abilities, significant gaps in the literature and heterogeneity in measurements limits the ability to make general conclusions. In addition, only 10 studies overall contain the highest quality evidence. Discussion and conclusions. Attentional resources may negatively impact motor speech performance in aging. Other cognitive abilities may also be involved but more evidence is needed. The same common cause responsible for age-related cognitive and sensory declines could therefore affect motor speech. Further research using a range of cognitive measures and constrained speech tasks is required to understand the effects of cognitive aging on motor speech performance.