The income gap between women and men expands with age, culminating in a gender pension gap in old age that is much larger than pay gaps earlier in life. In this article, I question two attempts to justify gender pension gaps. One insists that lower financial contribution justifies women's lower overall pensions. The second states that women must receive less monthly because they live longer. I argue that neither of these reasons is fair in a gender‐unjust world. Rather than justifying (...) pension gaps, female longevity is an opportunity to promote gender justice: by subsidizing longer lives, old‐age redistribution attenuates lifetime gender inequality. In the case of retirement pensions, the use of age to promote gender equality may be preferable to explicit gender differentiation. There is, then, a feminist case for old‐age redistribution. (shrink)