Based on a review of research, this article outlines patterns of support associated with in-law relationships in the United States. The analysis is organized in a four-part framework. The first part is devoted to parental aid to married children and indirectly to their spouses. Part two focuses on help patterns directed specifically toward children-in-law. In part three attention shifts to in-law support in later life, and part four addresses the effects of marital dissolution on in-law support. The article concludes with a discussion of how various demographic factors may affect the nature of the in-law support structure.