We examine dementia-related mortality in Spain during the period 2016–2021 from a multiple cause of death (MCOD) perspective, focusing on comorbidities associated with dementia-related mortality and the impact of dementia-related mortality on educational inequalities in life expectancy at age 60. We used mortality data from the Spanish National Statistics Institute (INE) by level of education from 2016 to 2021 to analyse mortality from dementia-related diseases, both as underlying cause of death (UCOD) and as MCOD. We estimated age-standardized mortality rates and used life tables and demographic decomposition techniques to assess the impact of dementia-related diseases on educational differences in life expectancy at age 60. Results showed that in 2016-21 MCOD dementia-related deaths accounted for 17% of all deaths occurring after the age of 60 (men: 11%; women 21%). The difference in years lost to MCOD dementia-related diseases between the most and least educated was 0.13 years (8.4%) for men and 0.26 years (22.7%) for women. Educational gradients in dementia-related mortality in Spain highlights the importance of disentangling risk factors from a socioeconomic perspective. Moreover, the MCOD approach provides a more realistic estimate of the impact of dementia-related diseases on life expectancy, bringing insights into the burden of ageing-related diseases.