AIMS: This study aims to explore the correlation between fear of dementia and insomnia among community-dwelling older adults and to examine the mediating roles of social isolation and resilience on this correlation. METHODS: A total of 259 community-dwelling older adults from Mianyang, China were recruited from June 2021 to August 2021 using convenience sampling. The Chinese versions of the Fear of Dementia Scale (FODS), Lubben Social Network Scale (LSNS-6), 25-item Connor-Davidson Resilience Scale (CD-RISC-25) and Athens Insomnia Scale (AIS) were used to collect specific, study-related information from the subjects. Correlations between variables of interest were examined by Pearson analysis, and mediation analysis was conducted to explore the direct, indirect and total effects of the fear of dementia on insomnia vis-à-vis social isolation and resilience. RESULTS: Results from 259 older adults indicated that fear of dementia and insomnia in older adults are positively correlated, that social isolation and resilience mediate the relationship between them, and that social isolation and resilience also had a statistically significant serial mediating effect. CONCLUSION: Fear of dementia is positively related to insomnia in older community-dwelling Chinese adults, but resilience and social support may buffer the negative impact of fear of dementia and improve sleep quality. IMPACT: Fear of dementia is becoming more and more common in community-dwelling older adults in China, and this emotional response to ageing and disease anxiety may be to blame for the poor sleep quality of some ageing populations. However, social support and resilience may buffer the negative impact of fear of dementia. The findings in this study indicate a need for well-trained community nurses and other health practitioners to implement targeted strategies to reduce insomnia among older adults with fear of dementia. These strategies should strengthen resilience as well as social support.