According to research on weight bias, relationship stigma may be greater among romantic couples comprised of at least one overweight partner, as compared to two healthy-weight partners. However, comparison theories predict that the stigma of being overweight may be greater among mixed-weight couples (i.e., romantic partners with dissimilar body mass indexes; BMI) than matched-weight couples (e.g., similarly overweight partners). To test these rival hypotheses, we assessed perceived and actual stigma experienced by mixed-weight and matched-weight couples. In two studies, people inferred (Study 1) or reported the actual amount (Study 2) of relational stigma and weight-related discomfort experienced by a healthy-weight/overweight person in a mixed/matched-weight relationship. Supporting the weight bias hypothesis, people inferred overweight people and their partners experience greater stigma and weight-related discomfort (Study 1). However, only overweight people in a matched-weight, as compared to mixed-weight, relationships actually reported greater relational stigma and weight-related discomfort (Study 2).