In this report, we use a panel of anonymized data derived from income tax returns filed between 1999 and 2010 and Social Security benefits data to study how the labor force participation of retirement-age couples responds to taxation. We examine the responses of primary and secondary earners of a couple using three different definitions of primary and secondary. First, given the age of this cohort, we assume that in each couple the wife is the secondary earner. Then we define the secondary earner either as having lower earnings two years previously or as having lower career earnings. We find that the retirements of women and secondary earners with lower career earnings are accelerated by taxes on their earnings while their spouses are not affected or are weakly affected. However, we find that the retirement decisions of women and workers with lower career earnings than their spouse are only affected by taxes when their spouses are not in the labor force.