Family planning represents a ‘best buy’ in global efforts to achieve sustainable development and attain improvements in sexual and reproductive health. Ensuring access is amongst key transformative strategies that underpin health and sustainable development. It confers fertility choices on women and couples within a human rights framework. By meeting contraceptive needs of all women, significant public health impact and development gains accrue. At the same time, governments face the complex challenge of allocating finite resources to competing priorities, each of which presents known and unknown challenges and opportunities. As such, there is a need to carefully consider the estimated costs and benefits for each proposed investment in health, education, social welfare, and security. Zambia has experienced a slow but steady increase in contraceptive prevalence, with slight decline in total fertility rate (TFR), over the past 20 years. Increasing voluntary modern contraceptive use among women offers opportunities to reduce unintended pregnancy while effectively harnessing the demographic dividend in order to bolster socioeconomic outcomes for households and communities. Drawing from the Zambian context, we present a case for making investments in voluntary family planning (FP), underpinned by a human rights framework, as a pillar for accelerating development and socio-economic advancement. Through multilevel interventions aimed at averting unintended pregnancies, Zambia – and other low- and middle-income countries – can reduce their age dependency ratios and harness economic growth opportunities awarded by the demographic dividend while improving the health and quality of life of the population.