While the average gender gap in pensions is quite well documented, gender differences in the distribution of pensions have rarely been explored. We show in this paper that pension dispersion is very similar for men and women within the French pension system of a given sector (public or private). However, the determinants of these gender inequalities are not the same. Using a regression-based decomposition of the Gini coefficient, we find that pension dispersion is mainly due to dispersion of the reference wage. Gender differences are less marked among civil servants. For women, pension dispersion is also due to dispersion in contribution periods. We also decompose the Gini coefficient by source of income to measure the impact of institutional rules on the extent of pension inequality. Unexpectedly, we find that the impact of pension minima is limited, although slightly larger for civil servants than for private sector employees.