INTRODUCTION: The study aimed to assess changes in the prevalence of dementia in Singapore over the past decade. METHODS: The Well-being of the Singapore Elderly (WiSE) 2023 and the WiSE 2013 studies were comprehensive, single-phase, cross-sectional surveys conducted among older adults aged ≥60 years in Singapore. WiSE 2023 included 2010 older adults and 1798 informants, whereas WiSE 2013 comprised 2565 older adults and 2421 informants. RESULTS: The weighted prevalence of dementia based on the 10/66 Diagnostic Research Group (DRG) criteria was 8.8% (95% confidence interval [CI]: 7.3-10.7) in the WiSE 2023 study compared to 10% in the WiSE 2013 study (95% CI: 8.7-11.5). The proportion of those with undiagnosed dementia decreased significantly from 70.6% in WiSE 2013 to 51.5% in WiSE 2023 (p-value = 0.002). DISCUSSION: A non-significant 12% reduction (95% CI: 1.1-3.5) in dementia prevalence was observed in Singapore over a decade, based on the WiSE 2013 and WiSE 2023 studies. HIGHLIGHTS: The prevalence of dementia decreased from 10% to 8.8% over a decade in Singapore. The prevalence varied by age group, ethnicity, employment status, and health factors. The prevalence of undiagnosed dementia decreased significantly from 70.6% to 51.5%.