Two key components of end-of-life planning are (1) informal discussions about future care and other end-of-life preferences and (2) formal planning via living wills and other legal documents. We leverage previous work on the institutional aspects of marriage and on sexual-minority discrimination to theorize why and how heterosexual, gay, and lesbian married couples engage in informal and formal end-of-life planning. We analyze qualitative dyadic in-depth interviews with 45 midlife gay, lesbian, and heterosexual married couples (N = 90 spouses). Findings suggest that same-sex spouses devote considerable attention to informal planning conversations and formal end-of-life plans, while heterosexual spouses report minimal formal or informal planning. The primary reasons same-sex spouses give for making end-of-life preparations are related to the absence of legal protections and concerns about discrimination from families. These findings raise questions about future end-of-life planning for same- and different-sex couples given a rapidly shifting legal and social landscape.