Background: While a large literature documents inequalities in healthcare utilization in Zambia, and the rest of sub-Saharan Africa, there has been limited focus on the examination of inequalities in family planning use and in general has increased, health inequalities persist. Similarly, despite the increase in utilization of family planning services from 15% in 1992 to 48% in 2018, the increase has not been equally shared in the population. We examine drivers of socio-economic related inequalities in utilization of family planning services among women of childbearing age in Zambia. Methods: Using secondary data from the 2014 Zambia Demographic and Health Survey (ZDHS), concentration curves and indices are applied to examine how pro-poor and pro-rich the distribution of family planning is. A Blinder-Oaxaca decomposition analysis is conducted to decompose the rural-urban differences in the utilization of family planning services among women of reproductive age. Results: Our findings show that less than half (45%) of the 12,498 respondents used family planning. Use of family planning services was unequally concentrated on the well-off (CI=0.590, P=0.055). The results are mainly driven by inequalities in rural areas (CI=0.4009, P=0.0730) as the distribution of family planning use in urban areas is more equal (CI=0.049, P=0.159). In addition to family planning use being more unequal in rural areas, the proportion of women who use family planning services is 5.16 percentage points lower than in urban areas. The factors accounting for the gap between rural and urban use of family planning, with a tendency to increase it, include wealth (54.79%), tertiary education (79.46%) and age-group of 45-49 years (53.68%). Some factors act to moderate, or reduce this gap and have negative contribution on family planning use. These include women with 7 and more children (-48.22%), being married (-43.45%), primary education (-33.93%) and middle wealth group (-43.75%). Conclusion: Despite progress in the utilisation of family planning services, socioeconomic inequalities have persisted, primarily in rural areas. Interventions to increase family planning use should aim at addressing rural socioeconomic disadvantage, with programs targeting poor women and those with low levels of education. Narrowing the rural-urban gap in family planning use should focus on improving wealth and education of rural women.