Introduction Recent evidence suggests that individual differences in attachment may be differentially associated with relationship status among heterosexual adults. However, sexual minority individuals face unique challenges, such as minority stress, that can impact relationship development, and thus research is needed to investigate singlehood among sexual minority adults. Methods A total of 1005 sexual minority adults participated in the current study (n = 481 long-term single; n = 524 partnered). Participants provided demographic information and completed measures of adult attachment and minority stress (internalized stigma, stigma consciousness, experiences of discrimination). Results Those who were single reported greater attachment anxiety and avoidance, and were higher in internalized stigma and stigma consciousness, compared to their partnered counterparts. In contrast, partnered individuals reported more experiences of discrimination. Finally, internalized stigma predicted long-term single status (single vs. partnered), over and above the effects of attachment insecurity. Policy Implications Results suggest that attachment and aspects of minority stress may be related to singlehood among some sexual minority adults. Social policy and professional practice implications are discussed, including the importance of increasing mental health practitioner awareness of the potential impacts of minority stress on both mental health and relationship issues.