A fertility gap—the difference between a woman’s ideal number of children and her actual number of children—is prevalent in both directions. We investigate the distribution of the fertility gap in India and factors that lead to women exceeding or underachieving their ideal number of children. We find that preference for males has a significant effect, contributing to a negative as well as a positive fertility gap. The probability that a woman exceeds her ideal number of children reduces by 7 percent in 2005–06 and 10 percent in 2015–16 if her first child is male. Further, we find that a husband’s preferences significantly shape the fertility gap. A woman is likely to exceed her ideal number of children by 3–4 percent if her husband prefers a higher number of sons than daughters. A husband’s ideal family size has an effect of similar magnitude as his son preference. Our results point to the important role of gender norms and household perspective in fertility analysis and policy settings and the challenges during fertility transitions.