Differential tax treatment of married and single people is a key feature of the tax law in the US and other countries. We develop a matching model with search frictions to analyze the effects these tax provisions have on marriage formation and dissolution. Our main results are the following: (i) although an increase in the 'marriage tax' reduces the number of marriages, there is a two-sided search effect that can substantially mitigate its impact on marriage formation and dissolution; (ii) an increase in the 'marriage tax' need not make both men and women more reluctant to marry; (iii) the effects of a given change in the differential taxation on marital behavior depend on whether it is implemented via changes in the tax rates that singles face or in the tax rates that married people face, as well as on the ability of the spouses to transfer utility between them; (iv) a computed example reveals that large changes in the marriage tax penalty can lead to small changes in the number of marriages and divorces, and that the number of divorces can increase with a reduction in the 'marriage tax'.
