Labor market and demographic developments are highly interrelated. This dissertation analyzes important intersections between the two. Its four chapters are based on large, mostly administrative micro data. The first three chapters apply innovative quasi-experimental methods, while the last chapter provides a descriptive analysis .The first chapter investigates empirically how maternal labor supply responds to an increase in fertility in the context of Mexico, where the average household income is low and informal child care and flexible employment opportunities are easily available. To overcome the endogeneity of fertility decisions, an instrumental variable approach that exploits parental preferences for a mixed-sex children composition is used. The rationale is that, compared to parents who have children of different sexes, parents with children of the same sex are more likely to have an additional child. At the same time, children's sex mix is assumed to be virtually randomly assigned. Relying on this instrument-induced variation, an increase in family size beyond two children is found to raise women's probability to be employed. This positive effect is driven by an increase in informal work, which tends to be easier to combine with child care responsibilities, and by low-wealth households, for which additional income is particularly valuable. Moreover, the presence of grandparents who potentially provide informal child care seems to be important. Further analyses support the internal validity of these findings. The effect of having more than two children on the propensity to be informally employed is bounded to be non-negative for all mothers in the sample, which supports the external validity of these results.The second chapter examines the labor supply responses of wives to a negative income shock experienced by their husbands for married couples in Austria. The empirical analysis is based on detailed administrative data and focuses on a sample where husbands lose their job due to mass layoffs or plant closures. Three different control groups are used to estimate the effect of husbands' job loss on spouses' subsequent labor supply. The main results are remarkably consistent across these groups. Husbands lose substantially both in terms of employment and earnings over a five-year period after displacement. The labor supply responses of wives are positive and statistically significant. However, the additional earnings generated by wives are small compared to their husbands' loss. Government transfers and taxes are more important providers of insurance, at least in the short run. Further results indicate that gender roles, preferences for time spent with children, and availability of formal child care play a strong role in the wives' labor supply decisions.The third chapter investigates how local labor markets are affected when receiving a large number of immigrant workers. The empirical strategy combines temporal variation in immigration resulting from the EU Eastern enlargement in 2004 and the later implementation of free labor market access to EU8 workers with the spatial variation that comes from the tendency of immigrants to go to municipalities that are close to their home country. The analysis based on social security data with information on both employees and employers finds significant changes in labor markets in the Austrian border region after 2004. First, the employment share of EU8 nationals in the region increases from 2.2\% in 1997 to 9.3\% in 2015. Second, this increase is larger in municipalities that are the closer to the border compared to those further away. Third, there is no decline in the employment of Austrian nationals, but average employment among non-EU8 foreign workers decreases significantly and steadily in municipalities with increased immigration after 2004. At the same time, Austrian workers experience an increase in their earnings, while non-EU8 foreign workers face substantial decreases. Finally, the number of firms is found to increase with immigration.The fourth chapter analyzes how mortality for mid-aged individuals is changing for several important demographic subgroups in Germany over the period from 1990 to 2015, with a focus on deaths from drug overdoses, suicides, and alcohol-related diseases, termed as deaths of despair. The results show a very clear pattern: mortality rates declined between 1990 and 2015, with no increases in deaths of despair for any of the subgroups. These findings starkly contrast with those for the US, where midlife mortality rates are increasing for white non-Hispanics since 1998.