A major transformation of life in the last decades has been the delay in fertility – that is, the decrease in fertility among people below age 25–30. At the same time that fertility has been delayed, the proportion of people having children later in life has increased, but in many countries, completed fertility has declined. In this chapter I (re)consider the extent to which these three phenomena –fertility delay, increase in later fertility, and fertility decline – are related. I examine whether fertility delay causes fertility decline and review evidence that an increasing number of people are facing constraints to childbearing in later life. Finally, I discuss the relevance of changes in partnership dynamics for fertility decline, as well as some implications of fertility delay on future completed fertility.I take a cohort and life course approach. While I acknowledge the temporality of fertility behavior and the importance of period “shocks” (e.g., recessions, pandemics), a cohort approach is the most natural way to examine the link between fertility timing (i.e., delay) and fertility quantum: the key question is, after all, whether the same people who delay fertility earlier in life wind up with fewer children at the end of their reproductive window. To explore overall trends as well as cross-country variation, I cover a range of low fertility countries at different stages of fertility delay and with different childbearing contexts over the 1940–80 birth cohorts.