Americans are convinced that employment stability has declined in recent decades, but previous research on this question has led to mixed conclusions. A key challenge is that trends for men and women are in opposite directions and appear to cancel each other out. We clarify this situation by examining trends in employer tenure by sex, marital status, and parental status. We find that married mothers are behind the increase in women’s job tenure, but men and never-married women have seen declines in tenure. Furthermore, we show that the timing of tenure trends for women parallels periods of increased labor force attachment. Finally, we find that shifts in industry and occupation composition can account for the decline in tenure among men and never-married women before 1996 but not afterward. We situate these diverging trends in two broad shifts in expectations, norms, and behaviors in the labor market: the end-of-work discourse and the revolution in women’s identification with paid work. Our findings support the view that job tenure is declining for all groups, but women’s greater labor force attachment, especially their more continuous employment around childbirth, countered and masked this trend.