An increase in correct usage of modern contraception is vital in reducing the maternal mortality ratio and Under-5 mortality, leading towards the achievement of Sustainable Development Goal 3. Our study examined the trends and factors affecting non-utilization of modern contraceptives over a 10-year period in Ekiti State, Nigeria. This study used data from three consecutive National Demographic Health Surveys (NDHS) - 2008, 2013, and 2018 - with a weighted sample size of 1,357 women of reproductive age (15-49 years). Data on contraceptive use on these women, provided by the NDHS, were extracted and analysed using IBM SPSS version 25. The sample was weighted to adjust for disproportionate sampling and non-response. Pearson's chi-square and binary logistic regression were used to assess the factors associated with non-utilization of modern contraceptives. The mean age of the women was 30 years. Modern contraceptive use increased from 13.1% in 2008 to 23.0% in 2018, while unmet need for modern contraceptives decreased from 84.8% in 2008 to 75.4% in 2018. Identified predictors of non-utilization of modern contraceptive were age 20-24 years [aOR=0.33, 95%CI=0.19-0.59], 25-29 years [aOR=0.34, 95%CI=0.18-0.64], 30-34 years [aOR=0.46, 95%CI=0.22-0.94], 35-39 years [aOR=0.29, 95%CI=0.14-0.61] and 40-44 years [aOR=0.37, 95%CI=0.17-0.80] compared to age 15-19 years; living in urban areas [aOR=0.72, 95%CI=0.53-0.98] compared to in rural areas; higher level of education [aOR=0.46, 95%CI=0.21-0.98] compared to no education; and desire for more children [aOR=0.48, 95%CI=0.32-0.73] compared to not wanting more children. Although contraceptive usage increased over time, the factors associated with non-utilization were being an adolescent, living in a rural area, lower level of education, and desire for more children.