The general decline in fertility levels in Pacific Asia has in its vanguard countries where fertility rates are among the lowest in the world. A related trend is toward delayed marriage and nonmarriage. When prevalence of cohabitation in European countries is allowed for, levels of “effective singlehood” in many countries of Pacific Asia have run ahead of those in northern and western Europe. This raises questions about the extent to which delayed marriage has been implicated in fertility declines, and whether the same factors are leading both to delayed marriage and to lowered fertility within marriage. The article argues that involuntary nonmarriage is likely to be more common in Pacific Asia than in Western countries, and that resultant involuntary childlessness plays a substantial role in the low fertility rates currently observed.