We provide new evidence on the effects of legal access to same-sex marriage on employer decisions about health insurance benefits for same-sex domestic partners of employees. No prior work has used high quality employer surveys such as those we propose to use here: the Medical Expenditure Panel Survey – Insurance Component has asked over 40,000 public and private employers about same-sex domestic partner health benefits since 2013. Together with restricted access to geolocation of the employer, we will examine how the rollout of legal access to same-sex marriage affected decisions about these benefits, and we will examine whether employer characteristics such as firm size or industry are systematically related to the effects of legal same-sex marriage on these employer decisions.