The aim of the present study was to report the usual nutrient intakes of sixteen micronutrients by schoolchildren, adults and the elderly in Greece and to further explore the role of age, sex and socio-economic status (SES) on meeting the recommended nutrient intakes. Dietary intake, demographic and SES data from three existing studies conducted in Greece (in 9-13-year-old children; 40-60-year-old adults; and 50-75-year-old women) were collected. The prevalence of study participants with inadequate micronutrient intakes were assessed using the estimated average requirement (EAR) cut-point method. Regarding sex and age differences, the highest prevalences of inadequate nutrient intakes occurred in post-menopausal women. In both sexes and all age groups, the prevalence of vitamin D intake below EAR reached 100%. Furthermore, nutrient intakes of 75% or more below EAR were found for vitamin E in all age groups, folate in women and for calcium and magnesium in post-menopausal women (p < 0.05). Regarding SES differences, the prevalences of inadequate calcium and vitamin C intakes were higher for children and postmenopausal women of lower SES compared to their higher SES counterparts (p < 0.05). The current study reported the highest prevalences of inadequate intakes for both sexes and all age and SES groups for calcium, folate and vitamins D and E. These findings could provide guidance to public health policy makers in terms of updating current dietary guidelines and fortifying foods to meet the needs of all population subgroups.